中学英语单词用法复习知识点once和onion和only等 on[ɒn] prep.○1在上面；在……期间；○2关于 There is a bottle of milk on the table.桌子上有瓶牛奶。 ► The accident happened on Monday morning.事故发生在星期一的早上。 ^ ► We are having a lesson on English.我们正在上英语课。 常用搭配► on time 准时 || on foot 步行 II later on 后来 II on show 展出(on display) || on the other hand 另一方面 II on the right 在右边 || on weekends 在周末 II on vacation在假期|| on stage在舞台上 On the other hand, it is not important to us at all. 另一方面，对我们来说根本不重要。 on a hot day 在炎热的一天，on the school trip 学校郊游，on school nights 学校郊游 背单词的好方法 随时随地背单词 不知不觉背单词 单词不用记 once[wʌns] adv.一次，曾经|| conj.①一旦②一......就...... ►I see them once every two months.我每两个月与他见一次面 ►Once you got into a bad habit，you'll  find it hard to get rid of it.你一旦染上坏习惯，想改掉就难了。 常用搭配►at once立刻，马上|| once more再一次|| once upon a time从前，||once or twice一两次 oneself[wʌn'self]  pron.自己，自身 ► If one wants to learn it，one must do it oneself. 一个人如果想学会它就得亲自去做。 onion['ʌnjən]  n. [C, U]洋葱，葱头 only['əʊnlɪ] adj.唯一的，仅有的|| adv.只，仅 ► She’s the only person for the job.她是这项工作唯一的人选。 选择填空 21. — What’s that?—It’s ________ book .    A. a B. the C./ D. an 22. — Is that green ruler yours, Sally?    — ________. My ruler is a yellow one.    A. Yes, it is. B. No, it isn’t. C. Yes, they are. D. No, they aren’t. 23. — What’s that in English? Can you ________ it, please?    — It’s a clock. C-L-O-C-K.    A. look B. finish C. spell D. take 24. The socks are six dollars for one pair. So I need _________ dollars to buy three pairs.    A. fourteen B. sixteen C. seventeen D. eighteen 25. Our school has a sports meeting ________ October 15th.    A. at B. in C. on D. of 26. — _________ Andy and Anna eat hamburgers for dinner?    — No, they like Chinese food.    A. Do B. Does C. Are D. Is 27. — Is he ________ now? — Yes. He has no time to have lunch with us.    A. busy B. free C. healthy D. late 28. For breakfast, Tom likes eggs, bread _________ milk.    A. but B. and C. / D. because 29. — What ________ does he like best? — Ping-pong.    A. food B. subject C. color D. sport 30. — ________ is your math teacher?    — My math teacher is Mr. Wang.    A. Where B. Who C. When D. Why 31. — Is this your math book?   — No, it isn’t. It’s ________. Her name is on it.    A. mine B. yours C. hers D. his 32. — Are they your __________?    — Yes, they are. They are my mom and dad.    A. pencils B. parents C. clothes D. computers  33. Peter _________ a baseball, but he doesn’t __________ a baseball bat.    A. have; has B. has; have C. have; have   D. has; has 34. — Have a good day!    — ________   A. You are welcome. B. Nice to meet you, too.   C. Thanks! You, too. D. I’m fine, thanks. 35. — ________?    — Because she doesn’t want to be fat.   A. Who is the girl there B. Why does your mother like the library   C. How is your mother D. Why does she play sports every day 答案： 21--25 ABCDC    26—30 AABDB    31--35CBBCD