1¡¢She looked sad, could you please tell me       that prevents her from being as happy as before?

A. what it is       B. it is what                           C. how it is D. it is how

2¡¢She asked me ___________ I had returned the books to the library, and I admitted that I hadn’t.

A.when                           B.where       C.whether       D.what

3¡¢The gold medal will be awarded to ___________ wins the first place in the bicycle race.

A.whomever                         B.wherever      C.whoever      D.whatever

4¡¢It is estimated thatChinahas over 770 million 4G users, which doubles ________ it was in 2015.

A.that              B.which             C.what              D.how

5¡¢He asked me _______.
A.when would I come back
B.why I hadn’t attended the meeting
C.how much did I pay for the mobile phone
D.whom was I going to the cinema with