宾语从句：在句子中起宾语作用的从句叫做宾语从句。
通俗的说就是一个句子做另一个句子的宾语. 主要跟在及物动词和介词之后。
一般由“引导词＋主语＋谓语＋其它”构成，其语序是述句语序。
如何判断：1．可以从整个句式看,宾语从句只能放在主句谓语动词之后。
2．从引导词看。
if充当宾语从句的连接词时，相当于whether，词义为“是否”，when 充当宾语从句的连接词时，意为“什么时候”。
3．从时态看。
if和when作连接词时，引导宾语从句要注意：从句的谓语动词的时态应根据主句的时态作相应的变化。
所以宾语从句的三大要素：时态语序引导词前世今生：I know you . you are right.→I know you are right. /I know that you are right.⏹引导词✧that (后面是述句) I believe that you are an honest boy.✧what which who I don’t know what they are going to d o. what are they going to do？whose whom Tell me whose PSP it is.（whose PSP is it？）where when Can you tell me where he lives?where does he live?Why how I know why he was late. (why was he late？)（特殊疑问句）✧if / whether（一般疑问句/是否） I want to know if Miss Gao is back.Is Miss Gao back？✧另外，含how的词组也可引导宾语从句。
主要有how old，how many，how much， how long，howoften，how far等。
如：Do you know how old he is？⏹语序：宾语从句的连词后要用述句语序。
（主谓语句，即引导词后面直接跟主语）Who can tell us ———— over there?A．what they talk about B．what do they talk aboutC．what are they talking about D．what they are talking about注意：what was the matter这个比较特殊，特殊疑问词在句中做主语时从句不改变语序。
⏹时态✧主过从过：主句是过去的时态，从句要变成相应的过去的时态。
从句动词过去式。
一般现在时→一般过去时；一般将来时→过去将来时；现在进行时→过去进行时；现在完成时→过去完成时✧主现从随便：主句是一般现在的时态，从句根据句子选择。
She says that she is a policewoman. She said that she a policewoman.She says that she will fly to Japan. She said that she fly to Japan.✧真理规律永一现：真理、自然规律永远是一般现在时。
The teacher said that the earth moves around the sun.宾语从句注意事项⏹主句的谓语动词是say，think，tell， know，hear，see，feel，mean，hope，wish，remember，forget等时，或主句的谓语动词是由形容词afraid，glad，sure，sorry 等作表语的系表结构时，后面常接that引导的宾语从句。
例如：He says that he wants to speak to the headmaster．他说他想和校长说话。
I think that we need to buy some meat for the party．我认为我们需要为聚会买些肉。
I'm sorry（that）he isn't here right now．对不起，此刻他不在。
⏹从句的引导词that能省略吗？that引导的宾语从句用来述事实，that本身无词义，在从句中不作任何成分，在口语中常常省略。
I guess （that）somebody else has borrowed it．我猜是别的人把它借走了。
I'm afraid（that） you'll have to wait．恐怕你得等一下。
注意：◆从句前面有插入语时，引导词 that不能省略；◆如果有两个并列的宾语从句，第二个从句的引导词that也不能省略。
She may tell you，for example，that she is interested in Chinese．例如，她可能会告诉你，她对汉语感兴趣。
Mr Read said（that）he taught English in a middle schoolin Beijing and that he came from Australia．里德先生说他在的一所中学教英语，他来自澳大利亚。
⏹连接代词和连接副词起引导宾语从句的作用，不再重复使用连接词，造成错误。
I can't see that what is over there．（×）此句中应去掉that。
⏹可用连接代词或连接副词引导的宾语从句的动词或短语动词有 see，say，tell，ask，answer，know，decide，find out，show，remember， choose等。
如：We can't decide who should go to Beijing first．我们不能决定谁应该先去。
Read the story below and find out who Father Christmas is．读下面的故事，弄清楚圣诞老人是谁。
⏹否定前移；及完成反意问句；主句是I ／We think ／suppose ／guess ／believe imagine / expect等，动词后跟宾语从句否定式时，应转移到主句上去，完成反意问句时，应与从句主/谓保持一致。
（注: 否定前移的条件是，主句主语是第一人称I .We）I don't think he is right ,is he? 我认为他是不对的,是吗？I don't believe they have finished their work yet, have they ?我相信/认为他们还没有完成那项工作例如：我认为鸡不会游泳。
误：I think chickens can not swim．正：I don't think chickens can swim．注意：上述情况变成反意疑问句时，附加问句要看从句，如果主句的主语不是第一人称，则附加问句要看主句。
试比较：I think he is wrong，isn't he？ He thinks he is right，doesn't he？⏹特殊疑问句变宾语从句五注意一、在引导词上，要将疑问代词或疑问副词变为连接代词或连接副词，引导宾语从句。
如：Whose bike is this？Does anybody know？→ Does anybody know whose bike this is？二、宾语从句的时态应与主句的时态保持一致。
如：When the train will arrive？He asked me．→ He asked me when the train would arrive．三、在语序上，要将疑问句语序改为述句语序。
如：Which one do you like best？She askedme．→She asked me which one I liked best．【注意】疑问句中主语之前的助动词若是 do／does ／did，变为宾语从句时，要先将其去掉，谓语动词再根据时态作相应的变化。
四、特殊疑问词在句中作主语，变为宾语从句时语序不变（时态应作相应变化）。
如：Who can answer the question？The teacher asked．→The teacher asked who could answer the question．五、特殊疑问句变为宾语从句后，用问号还是用句号完全取决于主句的句式：如主句为述句、祈使句，句末就用句号；如主句是疑问句，句末就用问号。
如：I don't know when we shall start tomorrow． Do you know when we shall start tomorrow？⏹宾主从句的简化⑴当主句的谓语动词是hope ，agree，wish，choose，decide，promise等，后面带宾语从句，且主从句主语相同时，可以简化成不定式结构作宾语。
We hope that we shall see you soon．→We hope to see you soon．She agreed that she would help me with my English．→She agreed to help mewith my English．⑵当主句谓语动词是know，learn， forget，remember等词时，后面带的宾语从句可简化成“疑问词＋不定式”结构，此时，主从句主语也须一致。
I really don't know what I should do next．→I really don't know what todo next．She didn't know whether she should go or not．→She didn't know whether to go or not．I have forgotten how I can open the door．→I have forgotten how to open the door．⑶当主句谓语动词是ask，tell， show，teach等，后带双宾语，且从句主语和间接宾语一致时，宾语从句可转化成“疑问词＋不定式”结构。
Could you tellme how Ican getto the postoffice？→Could you tell me how to get to the post office？Please tell me where I can find him．→Please tell me where to find him．但是，如果间接宾语和从句的主语不一致，一般不要把宾语从句简化，否则会产生歧义。