已知某凸透镜的焦距可能是5cm、10cm、20cm，为了检测该凸透镜的

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已知某凸透镜的焦距可能是5cm、10cm、20cm，为了检测该凸透镜的焦距，小明和小刚做了个实验，在实验过程中当光屏距凸透镜12cm时，可以在光屏上看到一个清晰的倒立缩小的像，据此请你帮助他们判断该凸透镜的焦距是多少．

答案

当像距v= 12 cm时，像为倒立缩小的实像，由此可判断像距在一倍焦距与二倍焦距之间，即f<12 cm<2f，解得6 cm<f<12 cm，因此可知凸透镜的焦距是10 cm．

完形填空

完形填空。
One day a rich woman lost her purse with a lot of money in it. So she made a 1 , “If anybody finds my purse and 2 it to me, I'11 give half the money to him.” 　　A poor man 3 the purse near a shop. He sent it back to the woman , but the rich woman 4 .“'There was an expensive ring in my purse besides money,"said the woman, “I won’ t give you half the money in my purse until you return it to me. ” “But I’ve never seen an expensive ring in 5 purse, ”said the man. 　　They began to quarrel(争吵).The man became 6 and took her to a judge(法官). 7 the judge heard what had happened to them, he said to the woman, “I'm sure that you have lost a purse, and there is an expensive ring in it.But there is 8 a lot of money in this purse. So I don't think it's yours. 9 sometime. Maybe somebody will give your purse back. " 　　Then the judge 10 to the man and said , “Take the purse home. If the owner doesn't come to get it back in two days, it' will be yours. ”
( ) 1. A. face ( ) 2. A. gets ( ) 3. A. had ( ) 4. A. kept her word ( ) 5. A. your ( ) 6. A. sad ( ) 7. A. Before ( ) 8. A. only ( ) 9. A. Wait for ( ) 10.A. ran	B. mistake B. shows B. knew B. changed her mind B. her B. angry B. Though B. truly B. Listen to B. came	C. promise C. points C. heard C. tried her best C. his. C. excited C. After C. nearly C. Look after C. went	D. conversation D. returns D. found D. pulled her down D. my D. worried D. If D. really D. Talk about D. turned

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单项选择题 A2型题

某地有20万人口，1998年全死因死亡2000人，同年有结核病患者600人，其中男性400人，女性200人；该年有120人死于结核病，其中100人为男性。该地1998年粗死亡率为（）

A.300/10万

B.60/1000

C.10/1000

D.100/1000

E.所给资料不能计算

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