21. Hurricane Sandy hit America violently.__________, about 140 deaths were caused by it.
A. As a rule B. As a consequence C．As usual D. As a result of
22. I doubt ____________all the people invited will come to attend the ceremony in such bad weather.
A. whether B. that C. how D. what
23. He _________ desperately in vain for something to say to break the silence.
A. thought about B. cast about C. talked about D. set about
