21 . Miyi is _____ most beautiful city, so it’s worth ______ second visit .
A. the ; the B. the; a C. a; the D. a ; a
22. The city is 1.500 kilometers ______ our school.
A. far away B. far away from C. far away D. away from
23. This dictionary is at least three times as thick as you borrowed from the library.
A. one B. that C. it D. those
