可以省略“It is time + 从句”表⽰的是说话⼈的个⼈愿望，意思是“本来到了做某事的时间，但是却与事实相反”，因此从句要⽤虚拟语⽓。
对现在虚拟⽤从句的谓语动词过去时，对过去的虚拟⽤过去完成时，对将来虚拟⽤“should+原形【should 可以省略】”。如：It is time (that) you got up. 你早该起床了。(事实上还没起来)It was time (that) he had done his homework yesterday. 他本该昨天就要完成作业。(事实上没有写完). It is time the Government backed up its advert campaigns with tougher measures.是政府采取更严厉的措施来兑现其宣传承诺的时候了It's + the/序数词+ time +to do sth.表⽰某⼈第⼏次做某事.例：It is my first time to write letter in English.这是我第⼀次⽤英语写信.It's + the+序数词+ time+ that clause.也表⽰某⼈第⼏次做某事.例：It is my first time that I've even written letters.这是我第⼀次⽤写信
