英语中的强调结构是 “ It is (was) ＋ 被强调部分 ＋ that 从句”。这种结构主要用于强调主语、宾语、表语、状语等。有时还可强调从句、介词短语和动名词短语等。强调句不但可以是肯定句、否定句，还可以是疑问句。为了能掌握强调句的各种变化形式，现举例分析如下：

例：He happened to meet his friend in this street yesterday.

(1) It was he who/that happened to meet his friend in the street yesterday.（强调主语）

(2) It was his friend whom/that he happened to meet in the street yesterday. （强调宾语）

(3) It was in the street that he happened to meet his friend.（强调地点状语）

(4) It was yesterday that he happened to meet his friend in the street. （强调时间状语）

从以上的(1)句看出强调主语指人时，可用who或that，(2)句强调宾语指人时，可用whom或that，但指物时只能用that。例如（5）（6）句：

例：This book is very instructive.

(5) It is this book that is very instructive.（只能用that）

例：He wants to borrow a book from the library.

(6) It is a book that he wants to borrow from the library.

       (3) 句强调地点状语，用强调句中的that，可别误认为是定语从句，用关系副词where;

       (4) 句强调时间状语，也可别误认为是定语从句，用关系副词when。

同时，被强调的主语或宾语还可被一个定语从句修饰。注意强调句中的that和定语从句中的关系词。

例：The house where he lives is very old.

(7) It is the house where he lives that is very old.

例：He picked up a wallet in which there was a lot of money.

(8) It was a wallet in which there is a lot of money that he picked up.

例：He found the necklace in the hotel where he lived.

(9) It was in the hotel where he lived that he found the necklace.

    除此之外，还可强调主语从句、状语从句、介词短语、动名词短语等。

例：What he said disappointed me.

(10) It was what he said that disappointed me. （强调主语从句）

例：He didn’t believe what others told him.

       (11) It was what others told him that he didn’t believe. （强调宾语从句）

例：I began to appreciate their beauty only when I reread his poems recently.

(12) It was only when I reread his poems recently that I began to appreciate their beauty. （强调时间状语从句）

例：He didn’t come to school because he was ill.

       (13) It was because he was ill that he didn’t come to school. （强调原因状语从句）

例：The mountain climber was rescued only with the help of the local guide.

       (14) It was only with the help of the local guide that the mountain climber was rescued. （强调介词短语）

例：We had finished Senior English BookⅡ by the end of last term.

(15) It was by the end of last term that we had finished Senior English Book Ⅱ. （强调介词短语）

例：Having good manners is seen by many people as a sign of cultural understanding and good tastes.

(16) It is having good manners that is seen by many people as a sign of cultural understanding and good tastes. （强调动名词短语）

例：Missing the last bus means walking home.

(17) It is missing the last bus that means walking home. （强调动名词短语）

再说not until 的强调句，not until不能分开，until 后面的句子不变。

例：He did not go to bed until he finished his homework last night.

(18) It was not until he finished his homework last night that he went to bed.

例：He did not go back home after the experiment until midnight.

(19) It was not until midnight that he went back home after the experiment.

强调句和陈述句一样，它也有一般疑问句和特殊疑问句。

例：(20) Is it you that have made such a mistake again? (一般疑问句)

(21) Wasn’t it on Saturday afternoon that he lost his cellphone? (一般疑问句的否定式)

(22) When was it that he did such a foolish thing? (特殊疑问句)

(23) Why was it that she didn’t dare to enter the classroom? (特殊疑问句)

注意辨别下列两个句子：(24) 句是时间状语从句，可译成汉语“当他回来时，已九点钟了。”(25) 句是强调句，可译成“他是在九点钟回来的。”

  (24) It was nine o’clock when he came back.

       (25) It was at nine o’clock that he came back.

强调句这种结构不能用来强调谓语，如果要强调谓语，要在谓语动词前加助动词do, does, 或did。

例：Do be a good student.

        She does like this novel.

        He did go to see his girlfriend two days ago.