题干

有两个共点力,一个力的大小是30 N,另一个力的大小是40 N,它们合力的大小可能是  

A:0  

B:50 N  

C:80 N

D:100 N

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答案(点此获取答案解析)

B

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    Last week I was in the boarding(登机)area of the airport excited about my Christmas trip home to see my parents. I was busy planning for the weekend,1 I was taken out of my daydreaming by an elderly woman talking 2 into her cellphone. She kept asking the person to 3 her where she was. She 4 the gate number again and again. She got a little louder each time she did that. Many people snickered(窃笑)because she was nearly 5 and thought how silly old people could be.

    Then I heard her say, “I'm 6, but I can't hear you. There seems to be something wrong with my hearing aid.” “That's too 7” I thought as I moved forward to board the flight. Then I noticed her 8 was becoming increasingly frantic(发狂似的)as she tried to understand the person on the other end of the phone. It was almost my 9 to board. I couldn't 10 looking back at the woman. It made me think how 11 I was to have my hearing. And I realized I could offer her some 12.

    I suddenly got out of the 13 and went to the woman. I showed her to 14 me the phone and shouted, “Let me help you. I'll tell you what the person is 15.” She looked at me and agreed 16. I took the phone from her,17 who I was, listened for a moment, and told the woman her husband was 18 her outside the airport as he could not enter the gate area. Finally, I pointed her in the 19 direction.

    It took me less than two minutes to finish the task, but my 20 in having been able to help her remains strong.