③问题是谁能代替他。

　　The question is who_can_take_the_place_of_him.

　　④我不知道他何时到达北京。

　　I don't know when_he_will_get_to Beijing.

　　(二)注意事项

　　1．引导名词性从句的连接代词和连接副词的区别。

　　(1)成分：连接代词在从句中作主语、宾语、表语或定语；连接副词在从句中作状语。

　　(2)意义：无论是连接代词还是连接副词，都有各自的意义。

　　That's where the accident took place.

　　那就是事故发生的地方。(作状语，意为"......的地方")

　　She didn't know who/whom we were talking about.

　　她不知道我们在谈论谁。(作介词宾语，意为"谁")

　　[即时演练2]

　　选词填空：when, why, how, which, what, who, whom

　　①Do you know when the train arrives.

　　②Can you tell me why you chose the topic to write an article.

　　③How I can make greater progress later is a problem.

　　④Which team will win is not clear.

　　⑤What I want to know is who took away my book.

　　⑥The problem is whom we should have do it.

　　2．引导名词性从句的连接代词what与that的区别。

　　(1)that只起连接作用，在从句中不充当任何成分，也无任何意义。

　　(2)what引导从句，除起连接作用外，还在从句中作主语、宾语、表语等成分，这时what具有两个含义：①保留疑问的意义，即"什么；什么样的"；②相当于"the thing(s) that/which"，即"先行词＋定语从句"的含义。

　　另外，what的此种用法还可以表示时间(the time that)、地点(the place that)、人物(the person that)、数目(the amount/number that)等不同概念。

　　Our income is now double what it was ten years ago.

　　我们现在的收入是10年前的两倍。

　　The trouble is that she has lost his address.

　　麻烦在于她弄丢了他的地址。

　　After what seemed a long wait, the results were announced.

　　经过了似乎漫长的等待之后，结果被宣布了。

[即时演练3]　单句改错