强调句的结构 ：

It + be +强调部分+that(或who)+句子其他成分。

可借助改为下面几种形式， 各强调一个不同的成分：

改写 Xuedong met your brother in the street yesterday.

是小冬昨天在街上碰到你弟弟的

It was Xuedong who (that) met your brother in the street yesterday.

小冬昨天在街上碰到的是你弟弟。

It was your brother that Xuedong met in the street yesterday.

小冬昨天是在街上碰到你弟弟的。

It was in the street that(不用where) Xuedong met your brother in the street.

小冬是昨天在街上碰到你弟弟的。

It was yesterday that (不用when) Xuedong met your brother in the street.

It be + 被强调部分（可以是句子）+ that

It was because her mother was ill that she didn't go to work.

因为她母亲生病所以她没去上班。

It be + 被强调部分(有定语从句修饰)+ that

It is in the town where you lived ten years ago that an ancient tomb was found.

是在你十年前住过的镇上发现的古墓。

3. pay off 取得成功

Her perseverance paid off because she won an award for the report.

她的坚持获得了成功， 因为她的报道获奖了。

Did your plan pay off?

你的计划成功了吗？

Her effort paid off.

她的努力成功了。

4. so long as = as long as 只要

You can go out so long as you promise to be back before 10 a.m.

只要你承诺晚上10点前回来， 你就可以出去。

So long as the weather stays fine, we can go swimming.