21. I find the _____ of buildings _____ under the sand.
A. remaining; buried B. remainders, bury
C. remains; buried D. remains, burying
22. I don’t think there _____ some problems with his body.
A. be B. used to being C. exist D. is
23. I wonder ______ you are free this afternoon. We’d like you to come to our party.
A. that B. if C. why D. when
24. He felt ill and __________ died.
A. at first B. above of all C. eventually D. at all