18. —Did you see the intelligent dolphins and their fantastic show at Sea Theatre?
—Yes. But I think it’s cruel to make them do ________.
A. jokes B. tricks C. trips D. offers
19. She was not persuaded _________ the truth of his statement.
A. of B. to C. at D. on
20. Cycling is a very useful way, especially in cities _______ bike paths have been built.
A. which B. that C. where D. what
21. The rate of unemployment in America after the worldwide economic crisis may be ______ reported earlier.
A. as twice high as B. twice as high as
C. as high twice as D. as high as twice
