题目

如图所示电路，电源电压保持不变，闭合开关S，将滑动变阻器的滑片P向右移动过程中A. 电压表V的示数不变B. 电流表A的示数变大C. 小灯泡的亮度变暗D. 电路的总功率变大 答案：【答案】A【解析】A．由图可知，闭合开关，灯泡与滑动变阻器并联，电流表A测量电路总电流，电压表测电源电压，所以滑片移动电压表的示数不变，故A正确；B．根据并联电路中干路电流等于各支路电流之和可知，总电流变小，即电流表A的示数变小，故B错误；C．当滑动变阻器的滑片P向右移动时，滑  In 1989 an 8. 2 earthquake almost flattened America,killing over 30,000 people in less than four minutes. In the middle of complete damage and disorder,a father rushed to the school where his son was supposed to be,only to 16 that the building was 17 .    After the unforgettable shock,he 18 the promise he had made to his son,u No matter 19 happens,I'll always be there for you!” And tears began to 20 his eyes. As he looked at the pile of ruins,it looked hopeless,but he kept remembering his 21 to his son. He rushed there and started digging 22 the ruins.   As he was digging,other helpless parents arrived,saying, “It's too 23 ! They’re all dead!24 , face reality,there's nothing you can do!” To each parent he responded with one 25 Are you going to help me now?” No one helped. And then he continued to dig for his son,stone by stone.   Courageously he went on alone because he needed to know 26 himself, “Is my boy T!or is he dead?” He dug for 8 hours. .. 12 hours. .. 24 hours. .. 36 hours. . , then,in the 38th hour,he 28 back a large stone and heard his son's 29 He screamed his son name, “ ARM AND!” He heard back, “Dad,it's me,Dad!I told the other kids not to worry. I told them that if you were alive,you would 30 me and 31 you saved me,they’d be saved. You promised, ‘No matter what happens,I'll always be there for you! ’ You did it,Dad!” “What's going on in there?” the father asked.“There are 14 of us left 32 33, Dad. We’re scared, 33 , thirsty and thankful you’re here. When the building collapsed,it made a 34 , and it saved us. ”“ Come out,boy! ”“No,Dad!Let the other kids out first,35 I know you’ll get me!No matter what happens,I know you’ll always be there for me!”16. A. know   B. discover   C. think   D. realise17. A. as flat as a pancake   B. as high as a mountain   C. as strong as an ox   D. as weak as a kitten18. A. memorised   B. forgot   C. kept   D. remembered19. A. what   B. how   C. which   D. who20. A. fill   B. flow   C. come   D. follow21. A. picture   B. promise   C. present   D. encourage22. A. for   B. through   C. out   D. into23. A. dark   B. early   C. thick   D. late24. A. Come out   B. Come again   C. Come on   D. Come off25. A. word   B. sound   C. row   D. line26. A. for   B. of   C. by   D. to27. A. lovely   B. living   C. alive   D. lively28. A. got   B. paid   C. sent   D. pulled29. A. breath   B. voice   C. noise   D. tone30. A. see   B. save   C. visit   D. miss31. A. when   B. because   C. even if   D. though32. A. for   B. behind   C. out of   D. over33. A. excited   B. happy   C. hungry   D. sad34. A. promise   B. space   C. room   D. triangle35. A. because   B. though   C. when   D. even though