21.The letter is from my sister, ______is working in Beijing.

　　A. which B. that C. whom D. who

　　22.In our factory there are 2,000 workers, two thirds of ____are women.

　　A. them B. which C. whom D. who

　　23.You're the only person ______I've ever met ______could do it.

　　A. who;/ B./; whom C. whom;/ D./; who

　　24.I lost a book, ______I can't remember now.

　　A. whose title B. its title C. the title of it D. the title of that

　　25.Last summer we visited the West Lake, ______Hangzhou is famous in the world.

　　A. for which B. for that C. in which D. what

　　26.I have bought such a watch _______ was advertised on TV.

　　A. that B. which C. as D. it

　　27.I can never forget the day _______ we worked together and the day ______ we spent together.

　　A. when; which B. which; when C. what; that D. on which; when

　　28.The way ______he looks at problems is wrong.

　　A. which B. whose C. what D./

　　29.This is the reason ______he didn't come to the meeting.

　　A. in which B. with which C. that D. for which

　　30.This machine, ______for many years, is still working perfectly.

　　A. after which I have looked B. which I have looked after

　　C. that I have looked after D. I have looked after

　　31.The reason ______he didn't come was ______he was ill.

　　A. why; that B. that; why C. for that; that D. for which; what

　　32.He is working hard, ______will make him pass the final exam.

　　A. that B. which C. for which D. who

　　33.That is not the way ______I do it.

　　A./ B. which C. for which D. with which

　　34.I have two grammars, ______are of great use.

　　A. all of which B. either of which C. both of that D. both of which

　　35.I want to use the same tools _______used in your factory a few days ago.

　　A. as was B. which was C. as were D. which