It is (was) +被强调部分+that(who)... 为了强调句子的某一成分（通常是主语、宾语或状语），常用强调结构：

It is (was) +被强调部分+that(who)...

表示强调的it在这种结构的

句子中作主句的主语。 原始句：Last night I saw a film in the Youth Palace.

强调主语：It was I that (or: who) saw a film in the Youth Palace last night.

强调宾语：It was a fiml that I saw in the Youth Palace last night.

强调地点状语：It was in the Youth Palace that I saw a film last night.

强调时间状语：It was last night that I saw a film in the Youth Palace.

一般讲，原句的谓语动词如果是现在或将来各种时态，用It is...that (who)...；如果原句谓语动词是过去各种时态，则用It was... that(who)...。 注意点 ①在强调主语时，that后的谓语动词要与被强调者保持人称和数的

It is I who am a teacher. ②即使被强调的主语是复数，主句中的谓语动词也用单数

It is they who often help me with my lessons. ③在强调时间、地点、原因、或方式状语时，不要用when,where,why

或 how ，而用that

It was because her mother was ill that she didn't go with us. ④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...。that 从句中的谓语动词用肯定式。

My father didn't come home until 12 o'clock last night.

It was not until 12 o'clock last night that my father came home. 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：

把is/ was提到it前面。

Did this happen in Beijing?

Was it in Beijing that this happened? ⑥特殊疑问句中只有疑问词可以强调，其强调结构是"被强调部分（通

常是疑问代词或疑问副词）+ is/was + it + that/ who + 其它部分?"

Where were you born?

句型为：It is/ was not until + 被强调部分 + that + 其它部分

原始句：He didn't go to bed until/ till his wife came back.

强调句：It was not until his wife came back that he went to bed.

此句型只用until，不用till。但如果不是强调句型，till, until可通

用；因为句型中It is/ was not ... 已经是否定句了，that后面的从句

要用肯定句，切勿再用否定句了。 谓语动词的强调 It is/ was ... that ...结构不能强调谓语，如果需要强调谓语时，用助动词do/ does或did。 Do sit down. 务必请坐。

He did write to you last week.上周他确实给你写了信。

Do be careful when you cross the street.

过马路时，务必（千万）要小心啊！

此种强调只用do/does和did ，没有别的形式；过去时用did，后面的谓语动词用原形。