一、it引导强调句型
1．强调句型的基本结构：It is/was＋被强调部分＋that/who＋其他成分
(1)此结构中it没有具体意义，只是引出被强调部分。
(2)此强调句型只能强调主语、宾语、状语，不能强调谓语。
(3)强调时间状语、地点状语、原因状语等时要用that而不能用when, where, because。
(4)被强调的成分是表示人的词时用who/that，而被强调部分是物时只能用that。如：
It is my mother that/who reminds me to get up on time every day.
每天都是我妈妈提醒我按时起床。
It was Mr Smith who/that/whom he turned to for help.
他是向史密斯先生求助的。
It was in the museum that I first saw this old ancient vase.
我是在博物馆里第一次见到这个古花瓶的。
It is every Sunday that they get together to have a good time.
每个星期天他们聚在一起来度过愉快的时光。
It was by train that they travelled to Tibet last summer.
去年夏天他们乘火车去了西藏。
