以下是上海新东方优能中学频道为大家分享的2019上海高考英语知识点：2019年高考一轮复习英语知识点 it的用法（3）

　　2、使用"It is/was…that"强调句型要注意的几点

　　（1）被强调部分指人时，其后除了用that之外，也可用who或whom。强调的是主语时，使用who；强调的是宾语时，使用whom。

　　It was Mary who picked up the wallet. 是玛丽拾到了那个钱包。

　　It was one of my old schoolmates whom I visited yesterday. 我昨天去看的是我的一位老校友。

　　It was Jack that I met in the park last week. 我上星期在公园遇到的是杰克。

　　It was her that I met in the park yesterday. 昨天在公园时里我遇到的是她。

　　(2)强调句的时态

　　一般说来，原句的谓语动词如果是现在或将来各种时态，则用句型"It is .... that(who, whom) ... 。"如果原句谓语动词是过去各种时态，则用句型"It was ...that(who, whom)...."

　　It was only when I reread his poems recently that I began to appreciate their beauty. 只是在最近我在读他的诗时才开始欣赏到它的美。

　　It is Smith who is leaving for Beijing tomorrow. 是史密斯先生明天去北京。

　　(3)在强调时间、地点、原因或方式状语时，不能用when、where、why或how，只用that。

　　It was because her mother was ill that she didn't go with us. 就是因为她母亲病了，她才没跟我们一起去。

　　It was in Shanghai that the Chinese Communist Party was founded on July 1, 1921. 中国共产党是在上海于1921年7月1日建立的。

　　注意：可用"It is/was because…that…"结构强调because引导的原因状语从句，如上例所示，但不能用该结构强调由since或as引导的原因状语从句，如不能说:It is everybody is here that let's begin our discussion.也不能说: It was as it was raining hard that they had to stay at home.

　　（4）强调"not...until"结构

　　在强调"not...until"结构中由until短语（或从句）表示的时间状语时，要用固定的强调句型"It is/was not until ... that ... 。" 其中that从句中的谓语动词用肯定式。

　　My father did not come until 12 o'clock last night.

　　= It was not until 12 o'clock last night that my father came home.昨晚直到十二点我父亲才回家。

　　It was not until his father came in that the boy began to prepare his lessons. 直到她爸爸进来时，那个男孩才开始复习功课。

　　It was not until she came to see us that we knew her mother was ill in bed. 直到她来看我们时，我才知道她妈妈卧病在床。

　　（5）在强调一般疑问句中的某一成分时，主句要用一般疑问句的语序。

　　Did this happen in Guangzhou?

　　=Was it in Guangzhou that this happened? 此事是在广州发生的吗？

　　Was it in 1969 that the American astronaut succeeded in landing on the moon？是在1969年美国宇航员成功登上月球的吗？

　　（6）特殊疑问句中只有疑问词可以强调，其强调结构是："疑问词+is/was it +that … ？"

　　When did you get to know her?

　　=When was it that you got to know her? 你是在什么时候认识她的？

　　（7）可以强调方式状语和以because引导的原因状语从句。

　　It was unwillingly that he did it for me. 他是不情愿地替我做的那件事。

　　It was because he was ill that we had to come back early. 正是因为他病了，我们才不得不早归。

　　（8）可以强调宾语补足语，当连系动词不是be，表语部分是名词性词组时，也可使用这种结构强调表语，但是，当连系动词是be时，不能强调表语。

　　It is white that they painted the house. 他们把房子漆成的是白色。（强调宾语补足语）

　　It is a chief engineer that he becomes now. 他现在担任的是总工程师。（强调表语）

　　（9）强调句的谓语动词除了可采用现在时和过去时的单数形式外，有时根据需要还可采用复杂的形式。

　　It must have been Mary that you saw just now. 你刚才看到的一定是玛丽。

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