21. Only if you put ______ sun there did the movements of the other planets in ______ sky make sense.
A. the; 不填 B. the; the C. 不填; the D. a; the
22. Wang Ping found the new surroundings difficult ______.
A. to tolerate B. to be tolerated C. tolerating D. being tolerated
23. Our car ______ on our way to school, so we had to walk there.
A. broke up B. broke off C. broke down D. broke away
