④在由及物动词与介词构成的固定搭配中宾语从句若作该动词的宾语，需借用it作形式宾语。
I leave it to your own judgement whether you should do it．
是否该做这件事，我让你自己判断。
We owe it to you that there wasn't a serious accident.没有严重的事故，我们把此归功于你。
(3)it用于强调句
It was she who/that had been wrong.（强调主语）就是她错了。
It was the girl whom/that I met just now.（强调宾语）我刚才碰到的就是这个女孩。
It was Tom whom the teacher had talkedto．（强调介词宾语）老师跟他谈话的就是汤姆。
It was on Monday night that all this hap-pened．（强调状语）就是在周一晚上，发生了这一切。
It was not until she took off her dark glasses that I realized she was a famous film star.（强调not until引导的从句）就是直到她摘下墨镜我才认出她是著名电影明星。
(4)it还可用于以下句型：
It is/has been+-段时间+since从句（自从……已多久了）
It is fjxie months since I arrived in NewYork.我到纽约已经5个月了。（终止性动词）来自www.Examw.com
It has been five months since he lived in New York.他不在纽约生活已经5个月了。（延续性动词）
注意：终止性动词表示从动作发生时算起；如果是状态动词或延续性动词，则从动作或状态结束时算起。
②It was/will be+ -段时间+before从句（在……之前有多长时间）
It will be several years before we meet again.我们要过好几年才能再见面。
It was not long before she learned those poems by heart.没过多久她就记熟那些诗了。中 华 考 试 网
③It be+时间+when从句（当……时是某个时间了）
It was next morning when we finished our work.到了第二天早晨我们才完成了工作。
④It is/was/will be+序数词+time+ that从句（从句必须用完成时态）
It is the first time that I have been here.这是我第一次来这里。
3．以数量为突破口巧辨代词
(1)两者中的一个用one，另一个用the other，形成one.…the other结构。
He got two books. One is a textbook,and the other is a novel.他买了两本书，一本是课本，另一本是小说。
(2)-定范围内，除去一部分人／物，剩余的全部用the others或用“the other+可数名词复数”。一定范围内，除去一部分后，剩余部分不是全部时，用others或“other+可数名词复数”。形成句式：some.…others.…“一些……另一些……”，some.…the others.“一些……其余的都……”。
Some are singing,and the others are dancing. -些人在唱歌，其余的人在跳舞。
