英语强调句的基本句式是 It is…that… 或 It was…that…，在这样的强调句中的 that 可以省略。如以下例句均摘自《薄冰英语惯用法词典》：
It was then (that) I made her acquaintance. 我就是那时候才认识她的。
It was in September (that) I first noticed it. 我在9月份才第一次注意到那件事。
It wasn't until last night (that) he realized his mistakes. 直到昨夜他才认识到他的错误。
It was because he was ill (that) we decided to return. 是因为他病了我们才决定回来。