强调句型
　　这里讲的强调句主要是以it为引导词的分裂句。其构成形式为：It is (was) +被强调部分+ that(who, which) + 句子的其他部分。被强调的部分通常为主语、宾语和状语。
　　It is only when one is ill that one realizes the value of health.
　　It is what you will do that is essential.

　　Note:
　　在被强调部分的后面，一般用that引出句子的其他部分。但是如果强调的部分是表示人的名词，那么也可用who;如果是指物的名词也可用which。
　　It was Jane that/who lent me the money.
　　It was this novel that/which they talked about last night.
　　如果强调的是原因状语从句，只能用because引导，不能由since, as或why引导。
　　It was because(不用since或as) he had never had the opportunity that John hadn’t learned to drive.

　　有三类句子成分不可以进行强调，即表语、谓语动词和由though, although,　whereas等引导的从句。
　　It is although he is young that he can speak four languages. (误)
　　Although he is young, he can speak four languages. (正)
　　It is whereas he prefers pop song that I like classical music. (误)
　　I like classical music whereas he prefers pop songs. (正)