what 引导名词性 从句的五种用法After_seemed a very long time, I opened my eyes and found myself in bed!A. what B. when C. that D. whichA I dont know what you mean.什么一、用法归纳 1. 表示“的东西或事情”“所 的”，相当 于“the thing that.; all that.; everything that.” Theyve done what they can do to help her. 他们已经尽力帮助了她。He saves what he earns. 他赚多少，积蓄多少。What Mary is is the secretary. 玛丽的职务是秘书。2. 表示“的人或的样子”（指抽象意义的人 ）相当于the person that（见66）：He is no longer what he was. 他已经不是以前的那个样子。He is what is generally called a traitor. 他就是人们通常所说的叛徒。Who has made Fred he is now? what3. 表示“的数量或数目”,相当于the amount/number that Our income now is double what it was ten years ago. 我们现在的收入是10年前的两倍。The number of the students in our school is ten times what it was before liberation.现在我校学生的数量是解放前的10倍。4. 表示“的时间”,相当于the time that： After what seemed like hours he came out with a bitter smile. 似乎过了几个小时他才苦笑着出来。The young girl was too frightened to speak, standing there for what seemed like hours. 小女孩吓得不敢说话，在那儿站了几个小时。5. 表示“的地方”,相当于the place that This is what they call Salt Lake City. 这就是他们称为盐湖城的地方。In 1492, Columbus reached is now called America. what 归纳总结：当名词性从句缺少主语、宾语 、表语，而缺少的这个词不是指具体的人 时，要首先考虑what巩固练习: 1. She has changed a lot. Shes no longer _she used to be. A. that B. what C. which D. 不填 2. The tobacco which is used to make cigarettes was first grown in_is now part of the United States.A. which B. that C. all D. what 3. No longer_Tom the man_he used to be.A. will; what B. was; what C. will; that D. is; that 4. What has made China_she is today?A. that B. what C. as D. which 5. The number of the students of the college has reached 8,000, twice _ it was when the college was opened ten years ago. A. what B. as much C. which D. that二、用法说明 (1) 这样用的what相当于“先行词+关系代词”， 所以其前不能有先行词： 你喜欢什么就拿什么吧。正：You can have what you like. / You can have everything (that) you like.误：You can have everything what you like.二、用法说明 (2) 有时what 可用作限定词，其后修饰一个名 词（见42）： I gave him what books I had. 我把我所有的书都给他了。He gave me what money he had . 他把身边带有的钱全给了我。(3) what 后的名词可以是复数名词或不可数名词 ，但通常不能是单数可数名词： 误：I gave him what book I had. A is to B what C is to D句型分析句型: A is to B what C is to D. 本句型的意思是“A对B而言正如C对D 一样”。其中what 的意思相当于 as（ 但在此句型不能用as代替）,作连词用, 引导状语从句。 Air is to us what water is to fish. 空气对于我们犹如水对于鱼。 其中介词to表示对比