21. It is the first time that I _______ this kind of moon cake.
A. enjoyed B. have enjoyed C. enjoy D. enjoying
22. It was because of bad weather __________ the football match had to be put off.
A. so B. so that C. why D. that
23. --Look! The telephone is broken. Someone damaged it ________ purpose.
--That may be right. But perhaps it was broken _________ accident.
A. on; by B. by; by C. on; on D. by; on
