They are smiling. There ______ much trouble solving the problem.
A. couldn’t beB. mustn’t be
C. can’t have beenD. mustn’t have been
— Did you go to last night’s concert?
— Yes. And the girl playing the violin at the concert _______ all the people present with her excellent ability.
A. impressedB. comparedC. conveyedD. observed
I’m sorry I’m busy now. If I ____ time, I would certainly go to the movies with you.
A. haveB. hadC. have hadD. had had
It rained heavily overnight and not until this morning __________.
A. had it stoppedB. did it stop
C. stopped itD. it stopped
Wechat intends to radically change the way ______ people use mobilephones.
A. /B. whichC. whyD. who
She stormed into the boss’ office ________ about her co-worker’s behavior.
A. complainingB. complained
C. having complainedD. to complain
