sat语法试题及答案SAT语法试题及答案1. 选择下列句子中语法正确的一项。
A) The book that I read yesterday was very interesting.B) The book that I read yesterday is very interesting.C) The book that I read yesterday were very interesting.D) The book that I read yesterday has been very interesting. 答案：A2. 下列句子中，哪个选项使用了正确的标点符号？A) The weather was hot, and humid, and sticky.B) The weather was hot and humid, and sticky.C) The weather was hot; and humid, and sticky.D) The weather was hot, and humid and sticky.答案：B3. 以下句子中，哪个选项的动词时态使用正确？A) I have been working on this project since last week.B) I was working on this project since last week.C) I had been working on this project since last week.D) I will have been working on this project since last week. 答案：A4. 选择下列句子中主谓一致正确的一项。
A) The team are playing well together.B) The team is playing well together.C) The players are playing well together.D) The players is playing well together.答案：B5. 下列句子中，哪个选项使用了正确的平行结构？A) She enjoys reading, to swim, and hiking.B) She enjoys reading, swimming, and hiking.C) She enjoys to read, to swim, and hiking.D) She enjoys reading, swimming, and to hike. 答案：B6. 选择下列句子中语法正确的一项。
SAT语法真题中的错误1、代词指代错误：代词的性、数、格;比较特别考点是one 和you 不能相互指代例：Even with(A) a calculator, you must have a basic understanding(B)of mathematics if one expects(C) to solve complex problems correctly. No error(E)分析：本题第一个代词是you,所以C错，应改为you expect。
因为one和you 不能互相指代SAT语法真题中的错误2、主谓一致错误：常见错误类型，比较简单送分题。
例：The bright (A)fiberglass sculptures of Luis Jimenez has received (B)critical acclaim not only (C) in his home state, New Mexico, but also in (D)New York.分析：本题显然主语sculptures是个复数而谓语动词has是个单数,所以主谓不一致，应该把B 改为have receivedSAT语法真题中的错误3、平行并列题型例：Each time Caroline turns on her computers, she has(A) to enter a company code, then her initials, and then enters a password (B)before she can begin working(C). No error(D)分析：B enters a password 前面出现了可爱的and,这个词决定了前后必须是平行并列，要求形式对称、概念对等、功能相同。
所以前面也应该有第三人称单数动词+名词的结构和enters a password并列，而前面出现的是her initials所以正确改法：去掉enters,这种考题在国内高考也经常考，这个考点因为出题频率特别的高。
SAT语法改错题中的十大常见错误还在为SAT语法改错题头疼吗？下面是为广大考生整理的SAT语法改错题十大常见错误。
希望对SAT考试备考有帮助！SAT语法改错题十大常见错误1：代词指代错误代词的性、数、格比较特别。
考生需要注意的是one 和you 不能相互指代。
例：Even with (A) a calculator, you must have a basic understanding (B) of mathematics if one expects(C)to solve complex problems correctly. No error (E) 分析：本题第一个代词是you,所以C错，应改为you expect。
因为one和you 不能互相指代。
SAT语法改错题十大常见错误2：主谓一致错误主谓不一致是比较常见的错误类型，这算是比较简单的送分题。
例：The bright (A) fiber glass sculptures of Luis Jimenez has received (B) critical acclaim not only (C) in his home state, New Mexico, but also in (D) New York. 分析：本题显然主语sculptures是个复数而谓语动词has是个单数,所以主谓不一致，应该把B 改为have received。
SAT语法改错题十大常见错误2：平行并列题型例：Each time Caroline turns on her computers, she has (A) to enter a company code, then her initials, and then enters a password (B) before she can begin working(C). No error (D) 分析：B enters a password 前面出现了可爱的and,这个词决定了前后必须是平行并列，要求形式对称、概念对等、功能相同。
OG Test 1Section 65.We generally think of Canada as the northern neighbor of the United States, and more thanhalf of the states extend farther north than Canada’s southernmost point.（A）States, and more than half of the states extend（B）States, and it is the case that more than half of the states extend（C）States, but more than half of the states extending（D）States, whereas more than half of the states are extending（E）States; however, more than half of the states extend6.The three volumes of memoirs by Wole Soyinka begin with his childhood in a Nigerianvillage and culminate with his years at the University of Ibadan, one of the best universities in West Africa.（A）begin with his childhood in a Nigerian village and culminate（B）that begin with his childhood in a Nigerian village and culminate（C）have begun with his childhood in a Nigerian village and culminating（D）beginning with his childhood in a Nigerian village and culminating（E）are begun as a child with in a Nigerian village and culminate7. Dressed in a crisp, clean uniform, it reflected the efficient manner of the tour guide as shedistributed maps for a walking tour of Canberra.（A）Dressed in a crisp, clean uniform, it reflected the efficient manner of the tour guide （B）Dressed in a crisp, clean uniform, the efficient manner of the tour guide was reflected （C）Dressed in a crisp, clean uniform that reflected the efficient manner of the tour guide （D）The crisp, clean uniform of the tour guide reflected her efficient manner（E）The crisp, clean uniform of the tour guide, a reflection of her efficient manner9. A review of the composer’s new symphony called it confusing because of its unusualstructure, and its melodious final movement makes it elegant.（A）structure, and its melodious final movement makes it elegant（B）structure, although elegant by having its melodious final movement（C）structure, and it is elegant with its melodious final movement（D）structure while having a melodious final movement makes it elegant（E）structure but elegant because of its melodious final movement11.The famous battle depicted in the film Braveheart took place in northern England, and manypeople assume that it was the Scottish Highlands.（A）and many people assume that it was（B）many people assuming（C）but many people assume it to be（D）not what many people assume（E）not, as many people assume, in13. From about A.D. 700 to 1600, sculptors created nearly 1,000 colossal rock statues on theA B Cremote and tiny Easter Island. No errorD E17. According to educational statistics, the average age of college students has risen quiteA B Cnoticeable over the past 25 years. No errorD E20. According to some demographers, the number of United States citizens aged 65 or older isA B Clikely to rise to 87 million by 2050. No errorD E25. As their brains mature neurologically, infants become more capable to distinguish the shapesA B Cand textures of the objects around them. No errorD E29.There is probably no story more dramatic than baseball’s great hitter and right fielder, HankA B C DAaron. No errorESection 102.The watercolors it has on display by the museum represent the era when Japan’s emergencefrom feudalism and isolation inspired its artists to explore new themes and techniques.（A）it has on display by the museum represent the era when（B）that it, the museum, is displaying represents the era of（C）on display at the museum represent the era when（D）displayed at the museum representing the era when（E）being displayed at the museum represents the era while3.The origins of the Teapot Dome scandal can be traced to the presidency of TheodoreRoosevelt, William Howard Taft, and Woodrow Wilson.（A）can be traced to the presidency of（B）can be traced to the presidencies of（C）happened in the presidency of（D）happening during the presidencies of（E）that happened in the presidency of9. In 1972, to reduce pollution in the Great Lakes, limits having been set by the United Statesand Canada on the amount of phosphorus that could be discharged into Lakes Erie and Ontario.（A）limits having been set by the United States and Canada（B）limits set by the United States and Canada（C）limits have been set by the United States and Canada（D）the United States and Canada have set limits（E）the United States and Canada set limits14. Acquaintances of Alexei have commented that he is at once annoying because of hisunpredictability but his imagination is still a delight.（A）but his imagination is still a delight（B）although he is delightfully imaginative（C）and he is delightful in his imagination too（D）while being imaginative and they are delighted（E）and delightful because of his imaginationOG Test 2Section 627.According to some theorist, what any particular bird can eat could change with even theA B C Dslightest variation in the shape of its back. No errorE23.At the conclusion of the novel The Great Gatsby, Nick Carraway, a young Midwesternerrecently arrived to New York, moodily watches the blinking green light at the tip of LongA B C DIsland. No errorESection 106.An artist who explores Mexican cultural themes, the art of Maria Elena is world renowned. （A）An artist who explores Mexican cultural themes, the art of Maria Elena is world renowned（B）To explore Mexican cultural themes, the work of artist Maria Elena is world renowned （C）Artist Maria Elena has explored Mexican cultural themes, the art of which is world renowned（D）An artist who has explored Mexican cultural themes, Maria Elena’s art is world renowned （E）Maria Elena is a world-renowned artist whose art explores Mexican cultural themes12.On October 13, 1955, at the Six Gallery in San Francisco, Allen Ginsberg read his poemHowl, being the inauguration of both a new style in poetry and the Beat movement.（A）Howl, being the inauguration of both（B）Howl, being inaugurated（C）Howl, it was the inauguration of both（D）Howl, whose inauguration of both（E）Howl, thus inaugurating both13.Indicating their desire to extend free enterprise Canadians elected a member of theProgressive Conservative Party, Kim Campbell, as Prime Minister in 1993.（A）Canadians elected a member of the Progressive Conservative Party, Kim Campbell, as Prime Minister（B）Canadians’ election of a member of the Progressive Conservative Party as Prime Minister was Kim Campbell（C）Kim Campbell of the Progressive Conservative Party was elected Prime Minister of Canada（D）the Progressive Conservative Party’s Kim Campbell was elected Prime Minister of Canadians（E） a member of the Progressive Conservative Party, Kim Campbell, was elected by Canadians as Prime MinisterOG Test 3Section 64.Nursing and physical therapy are an example of health-care fields that have shortages instaffing.（A）are an example of health-care fields that（B）are examples of health-care fields that（C）are examples where health-care fields（D）exemplifies a health-care field that（E）exemplify health-care fields where they6. The company maintains computer systems for small businesses, plus it will manage theirpayroll accounts.（A）businesses, plus it will manage（B）businesses, in addition it will manage（C）businesses and manages（D）businesses, and, additionally, they also manage（E）businesses, it manages10. To introduce itself to a wider audience, the little-known band sold its CD’s cheaply toenthusiastic fans, who in turn shared the music with friends.（A）sold its CD’s cheaply（B）sold their CD’s cheaply（C）sells its CD’s at a low price（D）prices their CD’s low for to sell（E）will sell its CD’s at a cheap price11. Twice as many bird species inhabit Ecuador as in North America.（A）as in（B）as inhabit（C）instead of in（D）when compared to（E）than21. Ms. Kovak proudly displayed her research group’s most ingenious invention, a vacuumA Bcleaner that empties its own dust bag when pressing a button. No errorC D22. Famous for their sticky feet, the gecko can run up walls and across ceilings as well as hangA B C Dfrom a surface by its toes. No errorE26. Traffic was heavy, so by the time Brianne finally arrived at the theater, we waited for her forA Ban hour, missing the entire first act of the play. No errorC D E28. Although familiar to us from representations in ancient art, war chariots are rare museumA Bartifacts because by the sixth century B.C. they were no longer used in battle. No errorC D E29. A volunteer organization, the Covington Soup Kitchen has been feeding needy families sinceA B1977, annually distributing nearly a million pounds of food each year. No errorC D ESection 105.The Poetry book Society is an organization in London that provides information and guidancefor all lovers of contemporary poetry and giving them discounts on books of poetry.（A）provides information and guidance for all lovers of contemporary poetry and giving them discounts on books of poetry（B）provides information, guidance, and the getting of discounts on books of poetry for all lovers of contemporary poetry（C）not only provides information and guidance for lovers of contemporary poetry but also gives them discounts on books of poetry（D）has been providing information and guidance for lovers of contemporary poetry and were giving discounts on books of poetry（E）are providing information and guidance for all lovers of contemporary poetry and having given them discounts on books of poetry11.Theodore Roosevelt was not just a great reformer; he was also a great president.（A）Theodore Roosevelt was not just a great reformer; he was also a great president（B）Theodore Roosevelt was not just a great reformer, and also a great president（C）Theodore Roosevelt was not just a great reformer; but also a great president（D）Great not just as a reformer, but Theodore Roosevelt was also a great president（E）Not just as a reformer, Theodore Roosevelt was also a great president13. In the novel, Jane Eyre must make many difficult choices, like when she forces herself toleave the house of Mr. Rochester, the married man she loves.（A）like when she forces（B）and, as an example, when she forces（C）for example, by forcing（D）as exemplified by when she forces（E）including forcingOG Test 4Section 73.The campus newspaper does not print as much world news as does my hometown.（A）as does my hometown（B）as does my hometown newspaper（C）compared to what my hometown does（D）like my hometown newspaper does（E）like the one in my hometown does11. Though heavily dependent on the government for business and information whileuniversities supply the space research center with talent, as a corporation it remains independent of both.（A）information while universities supply the space research center with talent, as a corporation it remains（B）information and on talent by universities, the space research center, a corporation（C）information and on universities supply for talent, the space research centre is a corporation （D）information, universities supply the space research center with talent, but it is a corporation16. Along the curve of island known as the Florida Keys lies a reef of living coral, the only oneA B Cof a kind in the continental United States. No errorD E18. Because he is absent when his rivals voted against his proposal, Selby is worried aboutA B C Dmissing future meetings of the board of directors. No errorE19.In those cities in which public transportation is adequate, fewer traffic problems occur andA Bpedestrians are rarely involved in accidents. No errorC D E24. Since some people are convinced that dowsing a method of finding underground water withA Ba Y-shaped stick, is effective, but others condemn the procedure as mere superstition. NoC D Eerror25. Intense preoccupation on technique appears to be the one trait that great pianists have inA B C Dcommon. No errorE27. Also supported by the commission was the proposed health clinics and the proposed centerA B Cto distribute information on job-training opportunities. No errorD ESection 104.Journalists should present a balanced view of the news but with their goal to stir discussionand unsettle complacent thinkers.（A）with their goal to stir（B）should also stir（C）aiming at the same time to stir（D）also trying to stir（E）its goal should also be in stirringcking good instruction, my mistakes in creating a graph to illustrate historical trends werenumerous.（A）my mistakes in creating a graph to illustrate historical trends were numerous（B）I made numerous mistakes in creating a graph to illustrate historical trends（C）there were numerous mistakes in creating a graph to illustrate historical trends（D）I created a graph to illustrate historical trends with numerous mistakes（E）the graph I made for illustrating historical trends had numerous mistakes12. By simply entering an Internet website or calling a toll-free number, a catalog order can beplaced for almost anything from cheesecakes to fully equipped desktop computers.（A）a catalog order can be placed（B）by placing a catalog order（C）they will place your catalog order（D）you can place a catalog order（E）your catalog order can be placedOG Test 5Section 64. The issue the council debated, which was whether repeal of rent control will improve housingor just increase profits for landlords.（A）debated, which was whether repeal of rent control will improve（B）debated was if they would repeal rent control would this improve（C）debated was the repeal of rent control would in improved（D）debated was will repealing rent control mean improvement in（E）debated was whether repeal of rent control would improve9. Although the English artist William Blake never having painted portraits, he regarded them asmerely mechanical reproductions that, despite their popularity, lacked true creativity.（A）Although the English artist William Blake never having painted portraits, he regarded them （B）The English artist William Blake never painted portraits, he regarded them（C）Never having painted a portraits, they were regarded by the English artist William Blake （D）The English artist William Blake never painted portraits, regarding them（E）The English artist William Blake never painted portraits because he regarded them22. Although the politician was initially very sensitive to be criticized by the press, he quicklyA B Cbecame more confident about responding to reporters’ sometimes pointed questions. No errorD E25. The decline in science education during the period had two causes: less funding for scientificA Bresearch with a decrease in jobs related to space and defense. No errorC D E26. The number of awards given this year to biochemists accentuate the significant gains beingA B Cmade in the study of the chemistry of living organisms. No errorD E28. Until it can be replaced by a faster, more efficient, and more economical means ofA Btransportation, trucks will carry most of the freight within and through metropolitan areas.C DNo errorE29. Nearly all of the editors of the magazine agree that of the two articles to be punished.A B CFujimura’s is the more exciting. No errorD ESection 104. No sooner had Andrea del Sarto traveled to France to work for the French king but his wifepersuaded him to return to Italy.（A）but his wife persuaded him to return（B）but his wife had him persuaded into returning（C）than he was persuaded by his wife that he will return（D）but he was persuaded by his wife into returning（E）than his wife persuaded him to return10. Until being widely hunted for its ivory and blubber in the eighteenth century, warlruses wereplentiful in the waters of the northeastern United States.（A）Until being widely hunted for its（B）Before having been widely hunted for its（C）Up to them being widely hunted for their（D）Until they were widely hunted for their（E）Before they have been widely hunted for their11. Jesse passed the California bar examination last year, and he has been practicing law inCalifornia ever since.（A）and he has been practicing law in California ever since（B）since that time he has practiced law there（C）where ever since he practices law（D）he has been practicing law in California since then（E）and since then is practicing law thereOG Test 6Section 616. The young fish were very tiny, yet each of them ate many times its own weight in solid foodA B C Devery day. No errorE24. The record left by fossils, the ancient remains of plants and animals, provide scientists withA Btheir primary source of information about prehistoric life. No errorC D E25. The exchange between the teacher and the student promotes learning far different from thatA Bwhich results as the student listens but does not participate. No errorC D E29. Available through the school’s guidance office is a job directory and a list of job referralAcenters that provide information for student in need of employment. No errorB C D ESection 102. The duties of a firefighter are often as dangerous as a police officer.（A）as a police officer（B）as those of a police officer（C）like a police officer（D）such as a police officer（E）like a police officer’s8. Having Florence Nightingale as their leader and a growing awareness of the need forcleanliness helped to bring about the establishment of standers of hygiene in hospitals.（A）Having Florence Nightingale as their leader（B）Having the leadership of Florence Nightingale’s（C）Florence Nightingale as their leader（D）To be led by Florence Nightingale（E）The leadership of Florence Nightingale9. An expedition was sent in 1949 to check a Turkish villager’s reporting he had seen theremains of Noah’s ark on Mount Ararat.（A）a Turkish villager’s reporting（B）the report of a Turkish villager（C）the reporting of a Turkish villager（D）that a Turkish villager who reported（E）the Turkish villager report sayingOG Test 7Section 45. Great literature, such as the Greek tragedies or the novels of Jane Austen, endures by theirspeaking directly and freshly to each new generation of readers.（A）by their speaking directly and freshly（B）by its speaking direct and fresh（C）because it speaks directly and freshly（D）because of speaking direct and fresh（E）since they speak with directness and freshness6. The services of architect I.M.Pei are always very much in demand considering that hisbuildings combine both beauty and an affordable price.（A）considering that his buildings combine both beauty and an affordable price（B）considering that his buildings combine both beauty and affordability（C）because his buildings combine beauty and affordability（D）because his buildings combine will combine not only beauty but also an affordable price （E）being that his buildings will combine both beauty and affordability7. The tragic story of Paolo and Francesca was the subject of a poem and a symphony, beingpopular throughout the nineteenth century.（A）The tragic story of Paolo and Francesca was the subject of a poem and a symphony, being popular throughout the nineteenth century（B）The tragic story of Paolo and Francesca was popular throughout the nineteenth century, where it is being made the subject of a poem and a symphony（C）The tragic story of Paolo and Francesca was popular throughout the nineteenth century, when it was the subject of both a poem and a symphony（D）Paolo and Francesca, whose tragic story was the subject of a popular poem and symphony throughout the nineteenth century（E）Being the subject of a poem and a symphony, the tragic story of Paolo and Francesca having been popular throughout the nineteenth century10. Just as Ireland has produced many famous writers and the Netherlands an abundance offamous painters, so Finland has provided a large number of famous architects.（A）so Finland has provided a large number of famous architects（B）Finland provides famous architects, and by large numbers（C）Finland’s contribution is to provide famous architects in a large number（D）and so then, for Finland, a large number of famous architects is provided（E）and like them Finland has provided a large number of famous architects11. Readers of the novice writer’s recent book have said that it is at once frustrating because ofits chaotic structure but its originality is still a delight.（A）but its originality is still a delight（B）although it is delightfully original（C）and it is delightful in its originality（D）while being so original as to delight them（E）and delightful because of its originality20. In 1850 Jim Beckwourth, a Black American explorer, discovered in the mountains of theA BSierra Nevada a pass soon becoming an important gateway to California gold-rush country.C DNo errorE22. The Mount Isa mine complex is one of the most highly mechanized in the world, plus beingA B Cthe largest single industrial enterprise in Queensland. No errorD E24. The warning in the plays is clear: unless we restore the integrity of the family, all traditionalA B Cvalues will disappear. No errorD E25. As a student becomes familiar with both early and contemporary Native American literature,Aone may notice that traditional stories have influenced recent ones. No errorB C D E26. John Edgar Wideman is regarded to be one of the most talented writers of the late twentiethA Bcentury and is often compared to such literary giants as Ralph Ellison and Richard Wright.C DNo errorESection 105. One result of the fire department’s new contract is that they can no longer offer overtime payon weekends.（A）One result of the fire department’s new contract is that they can no longer offer overtime pay on weekends.（B）As one result of it’s new contract, the fire department can no longer offer overtime pay on weekends.（C）One result of the fire department’s new contract is that overtime pay on weekends can no longer be offered to them.（D）The fire department’s new contract results in their no longer being able to offer them overtime pay on weekends.（E）One result of the fire department’s new contract are that offering overtime pay on weekends is no longer possible.10. Arelia believes that cloth draped over hills is an art form that cannot last long enough as awork of art either to please or influence future generations.（A）cannot last long enough as a work of art either to please or influence future generations （B）cannot last long enough as a work of art, for ages to come neither pleasing or influencing future generations（C）is not a lasting work of art that for ages to come will either please or influence future generations（D）is not a lasting work of art that will remain for ages pleasing and influencing future generations（E）will not last long enough either to please or to influence future generations11. The price of gold has been influenced by continued inflation and because people have lostfaith in the dollar.（A）because people have lost faith（B）because of the loss of faith（C）by people which have lost faith（D）losing faith（E）loss of faithOG Test 8Section 45. In response to the traditional assumption that all readers are basically alike, feminist criticshave emphasized that every woman reads from their own unique perspectives.（A）that every woman reads from their own unique perspectives（B）that every woman reads from her own unique perspectives（C）that all women reading from a unique perspective of their own（D）how women reading each have unique perspectives（E）how the unique perspectives of women are in their readings9. Today the primary role of advertising may be to appeal and persuade rather that what it oncedid, educating and informing.（A）what it once did, educating and informing（B）what it once did, which was educating and informing（C）what it once did, education and information（D）educating and informing, what it once did（E）what it once was, to educate and inform20. The use of irrigation in the once-arid region have increased the production of alfalfa and ofA B Cmany other crops as well. No errorD E21. Unfortunately, the opening of the new library complex, previously scheduled for nextA BSeptember, would be delayed for several months because of construction difficulties.C DNo errorE23. Given her strong sense of social justice, Burns vehemently protested over her party’s failureA B Cto support a tax decrease for senior citizens. No errorD ESection 108. The practice of renaming a street Martin Luther King Boulevard has been adopted throughmany cities in honoring the civil rights leader.（A）through many cities in honoring（B）through many cities to honor（C）in many cities; it was to honor（D）by many cities to honor（E）by many cities in honoring9. During the 1980’s, the income gap between the richest and the poorest Americans widenedsignificantly, while continuing to expand in the 1990’s.（A）significantly, while continuing to expand（B）significantly, and it continued to expand（C）significantly with continuing expansion（D）significantly, it continued expanding（E）significantly, continuing expanding14. High school graduates usually do not end up earning as much income as college graduatesdo, this being why so many high school students go on to pursue college degrees.（A）do, this being why so many high school students（B）do, this is why so many high school students（C）do; this fact explains why so many high school students（D）do; this fact explaining the reason for why so many high school students（E）do, explaining why so many high school studentsOG Test 9Section 33. Legend has it that medieval Chinese warriors using manned kites to survey enemy troopsanticipating modern aerial surveillance.（A）using manned kites to survey enemy troops anticipating（B）using manned kites to survey enemy troops and anticipate（C）using manned kites and surveying enemy troops, they anticipated（D）used manned kites to survey enemy troops, a technique anticipating（E）used manned kites surveying enemy troops, so anticipating techniques of5.The programmers always talked of having too much to do, but in truth they had a lesseramount of work to do than their colleagues.（A）they had a lesser amount of work to do than（B）their work was the least among（C）they were having less work to do than（D）the amount of work they had to do was the least of（E）they had less work to do than7. Unlike American architects who preceded him, Frank Lloyd Wright did not draw on classicalor European architecture for inspiration.（A）Unlike American architects who preceded him, Frank Lloyd Wright（B）Unlike the inspiration of American architects who preceded him, Frank Lloyd Wright （C）Frank Lloyd Wright’s architecture, unlike American architects who preceded him,（D）Different from the American architects who preceded him, Frank Lloyd Wright’s designs （E）Frank Lloyd Wright’s inspirations, different from American architects who preceded him,10. In Germany, foresters discovered that trees killed by acid rain had begun to die four yearsearlier, even though the trees had shown no signs of disease then.（A）earlier, even though the trees had shown no signs of disease then（B）earlier, but not showing any signs of disease then（C）earlier, no outward signs of disease had been shown then in the trees, however（D）earlier, without any signs of disease shown then（E）earlier, not then having shown any signs of disease, however。
