21. In _______ face of more and more dropout factories, many people prefer to be paid on _____ daily basis.
A. the; the B. a; 不填 C.the; a D. the; 不填
22. Sorry, I have no time left now. Can we discuss the matter ________ supper?
A. over B. on C. by D. at
23. The classroom is crowded with children_____ have poor eyesight, all of ____ interested in painting.
A. who; whom B. that; whom C. who; them D. that; who