一、大学英语三、四级语法归纳
二、时态和语态
I、时态
◇时态是表示动作发生的时间和表现方式的一种动词形式。每一种“时间＋方式”就构成一种时态。从时间上看，有现在、过去、将来和过去将来之分，从动作上看，有一般、进行、完成及完成进行之区别。（英语动词有16种时态）在实际应用中以及TOEFL等考试中出现最多的时态也只有4种，即一般现在时，现在完成时，一般过去时及过去完成时。◇
1．用一般现在时表示将来的动作。
B.在由连词even if, unless, as soon as, if, when, in case, before, after, until, once, the
moment, as long as等引出状语从句中，谓语一般不用will或shall来表示将来的动作，仅用一般现在时。例如：
C.eg. She will come to see you the moment she finishes her work.
◇The boss won’t give the workers pay unless they ______their work today.
(03/12, 43)
D.A) finish B) finished C) will finish D) had finished
◇Such crimes may be so complex that months or years go by before anyone__________ them.
E.A) discovered B) will discover (03/1,31, CET-4)
F.C) would have discovered D) discovers
G. B. 某些表示起始的动词，可用一般现在时表示按预定计划或时刻表在短时间内将发生
的动作。这类动词有：be, go, come, start, leave, depart, arrive, begin, return等。例如：◇The train leaves at five sharp.
H. 2. 现在完成时、过去完成时以及将来完成时之间的区别
1)现在完成时：
I.①构成：have／has + 过去分词
J.②语法意义及要点：
A.表示一个过去开始的状态或动作持续到现在并可能继续持续下去，常同表示一段时间
的状语连用。eg. so far，up to now，since，for a long time etc.
K.eg. He has worked as a teacher for many years
L.Up till now，nothing has gone wrong．
◇Don’t disturb Father. He ________ letters all morning and has written ten so far. (99/6, 42)
M.A) write B) has been writing C) has written D) was writing
N.◇This is the worst time of the year. It ________every day so far.
(02/6, 42)
O.A) is raining B) has rained C) rained D) rains
P.B．表示一个过去发生的对现在仍有影响的动作或事件。常与不确定的过去时间状语连用(eg. yet，just，before，recently, etc.)；也同表示频度时间状语连用(eg. often，ever，never，sometimes，several times, etc).；还可同包括现在时间在内的时间状语连用(eg.
now，today，this morning, etc). 但不能同特定的过去时间状语连用(last year，inl997 etc.)
Q.eg. I have never learned Japanese before．
R.We have been quite busy lately /recently．
S.◇I am meeting Ivan tonight; I _______a Russian before.
(01/1,49)
T.A) didn’t ever meet B) have ever met C) had never met D) have never met
U.C．在时间或条件状语从句中，当表示将来完成时的意义时，要用现在完成时来代替将来完成时。
◇We'll start at 5 0'clock if it has stopped raining by then．
◇I shall go to see you when I have finished my homework．
V.Note：行为不能持续的瞬间动词(Instantaneous Verb)，eg. arrive, begin, come, go，start, leave, die，join，etc. 通常不能用于这一语法意义，即该类动词在现完成时中不能与表示一段时间的状语连用。
◇He has joined the army for five years．(F)
◇He has been in the army for five years。(T)
W.2) 过去完成时：
X.①构成：had+过去分词
Y.②语法意义及要点：表示某一动作或情况发生在过去某一时刻之前并持续到该时刻。Z.eg. David and Jenny had known each other for a long time before their marriage. AA.T hey had got everything ready before the party began．
◇The burglary ______before I arrived at the office; all I could do was to call the police. (03/6, 56)
BB.A) has occurred B) had occurred C) was occurring D) would occur
CC.N ote: 与现在完成时不同的是过去完成时可以与表示具体过去的时间状语连用。
◇He said that he had seen her the day before yesterday.
DD.3) 将来完成时：
EE.①构成：shall／will +have+过去分词
FF.②语法意义及要点：表示某一动作在将来某一时刻或将来某一动作之前已经完成或发生。
GG.eg. He will have graduated from high school before his next birthday，
HH.The shop will have closed already before you get there．
II.◇By the end of next year they _________together for twenty years. (01/1,48) JJ.A) will have worked B) had worked C) would work D) have worked
KK.◇--"May I speak to your manager Mr. Williams at five o'clock tonight?"
(00/6,41, CET-4)
--"I'm sorry. Mr. Williams _______ to a conference long before then."
A) will have gone B) had gone C) would have gone D) has gone
LL.◇By the time he arrives in Beijing, we_______ here for two days. (01/6,31, CET-4)
A) have been staying B) have stayed C) shall stay D) will have
stayed
MM.◇By the time you get to New York, I _______for London. (02/1,41, CET-4)
