宾语从句
宾语从句是一种名词性从句，在句中作及物动词的宾语，或介词的宾语，或形容词的宾语。根据引导宾语从句的不同连词，宾语从句可分为三类。
1.由that引导的宾语从句。that只有语法作用，没有实在的意义，在口语和非正
式文体中可以省略。
如：He said （that） he wanted to stay at home. She doesn't know （that）she is seriously ill.
I am sure （that） he will succeed. We knew（that）we should learn from each other.
2. 由连接代词who, whom, whose, what, which和连接副词when, where, why, how
引导的宾语从句。这些连接代词和连接副词在宾语从句中充当某个成分。
如：Do you know who（whom）they are waiting for He asked whose handwriting was the best.
Can you tell me where the bus stop is I don't know why the train is late.
Can you tell me how I can get to the nearest post office
3. 由if或whether引导的宾语从句。If和whether在句中的意思是“是否”。
如：I want to know if（whether）he lives there. He asked me whether（if）I could help him.
Please tell me if（whether）you have been to America.
注意：if和when既能引导时间状语从句，又能引导宾语从句。故遇到它们就要认真分析一下，它们属于哪种从句。
比较：If it rains tomorrow, I won’t come.（时间状语从句）
I don’t know if it will rain tomorrow. （宾语从句）
攻克宾语从句的三大秘笈
秘笈一：引导词
①如果从句是陈述句，引导词用that（that在口语或非正式文体中常省略）；如果从句是一般疑问句，引导词用if/whether；②如果从句是特殊疑问句，引导词用由特殊疑问词即what，when，where等转换而来的宾语从句。
如：I think（that）he will come here by train. 我认为他会坐火车来这儿的。
He asked me if / whether I know his new address. 他问我是否知道他的新地址。
I want to know when you got back home yesterday. 我想知道你昨天什么时候到家的。
秘笈二：语序
①宾语从句的语序为陈述句语序，即“主语+谓语+宾语+其他”。也就是说，将疑问句转化成宾语从句时，一定要将疑问句语序转变成陈述句语序。
如：Can you tell me what he will do tomorrow 你能告诉我他明天将要做什么吗
注：当疑问句在宾语从句中做主语时，语序不变。
如：Do you know what makes him so excited 你知道什么事使他如此兴奋吗
I don’t know what is wrong with him.我不知道他出什么事了。
②一般疑问句和特殊疑问句变为宾语从句，语序变为陈述语序。
如：Does he work hard I wonder. →I wonder if/whether he works hard.
When did he leave I don’t know. →I don’t know when he left.秘笈三：时态
主句为一般现在时态，则宾语从句根据实际情况用任意的时态；但主句为一般过去时态时，宾语从句则要用过去的相对应的某种时态。例如：
She tells me that she will come by bus. She told me that she would come by bus.
He said（that）there were no classes yesterday. I have heard（that）he will come back next week.
注：如果宾语从句表示的是客观真理或是科学事实，不管主句是什么时态，从句都要用一般现在时。
如：He said that light travels much faster than sound.
Our teacher told us that the sun is much bigger than the moon.
宾语从句中的从句的简化
1.当主句谓语动词是find，see，watch，hear等感官动词时，从句常简化为“宾语
＋宾补”结构，宾补为不带to的不定式或V-ing形式。
如：She found that the wallet was lying on the ground. →She found the wallet lying on the ground.
2.当主句谓语动词是hope，wish，decide，forget，plan，agree等，且主句主语
与从句主语相同时，从句可简化为不定式结构。
如：She agreed that she could help me with my maths. →She agreed to help me with my maths.
3.在连接代词/副词引导的宾语从句中，当从句主语与主句主语或间接宾语一致时，
宾语从句可简化为“连接代词/副词＋不定式”结构。
如：Can you tell me how I can get to the station →Can you tell me how to get to the station
宾语从句中的人称变化和标点的使用
1.从句的主语如果是第一人称，变为宾语从句则与主句的主语一致；如果是第二人
称，则与主句的宾语一致；如果是第三人称，不用变化。
如：“May I use your knife” He asked me. →He asked me if he might use my knife.
“Do you know her telephone number” He asked me.→He asked me if I know her telephone number.
