16.　　　 It took my three hours to do this.

15.　　　 It is easy (for sb) to do sth ( difficult, hard….)

14.　　　 It is time (for sb) to do sth.

13.　　　 It is important (for sb) to do sth(necessary…)

12.　　　 It doesn’t matter if ( that) he will come with you

11.　　　 It doesn’t matter whether he will come or not.

10.　　　 It makes no difference whether I will go there.

9.　　　　　 It is not settle whether I am going to American.

8.　　　　　 It is very unwise quarreling with him

7.　　　　　 It is a waste of time talking to you.