1) It is time (for sb.) to do sth. 到某人做某事的时间了

　　例如：It is time for the students to do morning exercises

　　到学生们做早操的时间了。.

　　2) It is + 形容词(+of / for sb.)+ to do sth.对某人来说做某事是…的

　　通常用 of的词有brave、clever、careful、hopeless、kind、good、naughty、nice、silly、stupid、foolish、wise等。

　　例如：It is wise of him to get rid of this bad habit.

　　对他来说， 改掉这个坏习惯是明智的。

　　3) It is no use/ good + doing sth.做某事是没用的

　　例如：It is no use complaining the bad working condition.

　　抱怨恶劣的工作条件是没有用的。

　　4) It’s not until… that...直到….才….

　　例如：It’s not until she told me that I knew the truth of fact.

　　直到她告诉我时我才知道事实的真相。

　　5) It is said/reported/announced/ (well) known … that…

　　据说(报道….)

　　例如：It is reported that some workers were buried under the ground.

　　据报道一些工人被埋在地下。

　　6) It is/was + 时间 + since … 从……已多久了。

　　例如：It is a long time since we have met last time.

　　我们上次见面到现在有很长时间了