1）It's time to do sth 如 It's time to go.
2）It's time for sb to do sth 其中sb为宾语,当sb是代词时,用宾格,如It's time for us to sleep.
3）It's time that +从句 用于虚拟语气,从句为故去时态
如：It's time that we went to sleep.