what引導名詞性從句用法：
1.表示“……的東西或事情”：
They’ve done what they can to help her.他們已經盡力幫助了她。
He saves what he earns.他賺多少，積蓄多少。
What Mary is is the secretary.瑪麗的職務是秘書。
2.表示“……的人或的樣子”：
He is no longer what he was.他已經不是以前的那個樣子。
He is what is generally called a traitor.他就是人們通常所說的叛徒。
Who is it that has made Fred what he is now? 是誰把弗雷德培養成現在這個樣子的？
3.表示“……的數量或數目”：
Our income is now double what it was ten years ago.我們現在的收入是10年前的兩倍。
The number of the students in our school is ten times what it was before liberation.現在我校學生的數量是解放前的10倍。
4.表示“……的時間”：
After what seemed like hours he came out with a bitter smile.似乎過了幾個小時他才苦笑著出來。
The young girl was too frightened to speak, standing there for what seemed like hours.小女孩嚇得不敢說話，在那兒站了幾個小時。
5.表示“……的地方”：
This is what they call Salt Lake City.這就是他們稱為鹽湖城的地方。
In 1492, Columbus reached what is now called America.1492年哥倫布到達了現在所稱的美洲大陸。