问题 填空题

一个焦距为10cm的凸透镜,当蜡烛距它15cm时,在光屏上得到一个倒立、______(填:“放大”、“缩小”或“等大”)的像;将蜡烛向透镜移近7cm后,在光屏上______(填:“能”或“不能”)成像.

答案

(1)凸透镜的焦距是10cm,蜡烛距离凸透镜15cm,2f>u>f,光屏上成倒立、放大的实像.

(2)凸透镜的焦距是10cm,蜡烛距离凸透镜7cm,u<f,成正立、放大的虚像,虚像不能呈现在光屏上.

故答案为:放大;不能.

完形填空

Jenlins was a jeweller, who had made a large diamond(钻石) ring worth 57,000 pounds for the Silkstone Jewellery Shop. When it was ready, he made a copy of it which looked ___1___ like the first one but was worth only 2,000 pounds. This he took to the shop, which ___2___ it without a question.

Jenkins gave the much more ___3___ ring to his wife for her fortieth birthday. Then, the husband and wife ___4___ to Paris for a weekend. As to the ___5___ ring, the shop sold it for 60,000 pounds.

Six months later the buyer ___6___ it back to Silkstone’s office. “It’s a faulty(有瑕疵的) diamond,” he said. “It isn’t worth the high ___7___ I paid.” Then he told them the ___8___. His wife’s car had caught fire in an ___9___. She had escaped(幸免), ___10___ the ring had fallen off and been damaged(损坏) in the great ___11___ of the fire.

The shop had to ___12___. They knew that no fire on earth can ___13___ damage a perfect diamond. Someone had taken the ___14___ diamond and put a faulty one in its place. The question was: who ___15___ it?

A picture of the ring appeared in the ___16___. A reader thought he ___17___ the ring. The next day, another picture appeared in the papers which ___18___ a famous dancer walking out to a plane for Paris. Behind the dancer there was a woman ___19___ a large diamond ring. “Do you know the ___20___ with the lovely diamond ring?” the papers asked their readers. Several months later, Jenkins was sentenced to seven years in prison.

1. A. only       B. surely C. nearly D. exactly

2. A. accepted B. received     C. refused       D. rejected

3. A. real B. modern      C. worthy       D. valuable

4. A. flew       B. drove  C. sailed  D. bicycled

5. A. first       B. second       C. last     D. next

6. A. sold       B. posted C. brought      D. returned

7. A. cost       B. money       C. price   D. value

8. A. facts      B. matters       C. questions    D. results

9. A. affair     B. accident     C. incident      D. experience

11. A. pile      B. heat    C. power D. pressure

12. A. think    B. agree  C. permit D. promise

13. A. almost  B. even   C. just     D. ever

14. A. real      B. pure    C. right   D. exact

15. A. copied  B. made  C. stole   D. did

16. A. notices B. magazines  C. newspapers D. programmes

17. A. saw      B. knew  C. found  D. recognized

18. A. showed       B. drew   C. printed       D. carried

19. A. carrying      B. dressing     C. wearing      D. holding

20. A. dancer  B. woman       C. reader D. jeweler

单项选择题