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问题 解答题

某次知识竞赛共有20道选择题．对于每一道题，若答对了，则得10分；若答错了或不答，则扣3分．请问至少要答对几道题，总得分才不少于70分？

答案

设至少要答对x道题，总得分才不少于70分，则答错或不答的题目共有（20-x），

依题意得：10x-3（20-x）≥70

10x-60+3x≥70

13x≥130

x≥10

答：至少要答对10道题，总得分才不少于70分．

听力题

单词拼写（共10小题；每小题1分，满分10分）

51. I must a__________ to you for not being able to meet you at the airport.

52. There has been an 8% d__________ in his income because of the financial crisis.

53. Though time was l_________, we finished the work on time.

54.A lot of people a__________great importance to becoming rich and famous.

55.I will a__________ it if you can help us with the work.

56. Nobody is admitted to the building without p_____________of the police.

57. C__________drove him to open the letter addressed to his sister.

58.He played the violin beautifully by the side of the street and many p_________ put coins into his hat on the ground.

59.He s__________ in the final examinations and was awarded the first prize.

60. Mary used to sing songs in a pub to earn some e___________ money when she was a college student.
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单项选择题

关于景深描述不正确的（）.

A.镜头焦距短，景深区较大

B.镜头焦距短，景深区较大

C.摄像机离物体越近景深越小

D.俯拍景深区大
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