问题
选择题
7个连续质数从大到小排列是a、b、c、d、e、f、g．已知它们的和是偶数，那么d=（ ）
A．7
B．11
C．13
D．17
答案
因为7个连续质数的和为偶数，根根据数和的奇偶性可知：
其中一个数应既为质数又为偶数，即a=2，
则这7个连续质数为：2、3、5、7、11、13、17；即d=7．
故选：A．
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7个连续质数从大到小排列是a、b、c、d、e、f、g．已知它们的和是偶数，那么d=（ ）
A．7
B．11
C．13
D．17
因为7个连续质数的和为偶数，根根据数和的奇偶性可知：
其中一个数应既为质数又为偶数，即a=2，
则这7个连续质数为：2、3、5、7、11、13、17；即d=7．
故选：A．
Mrs. Black was a famous musician a few years ago. She 1 music at a school and her students did well in their lessons. They liked her very much. Now the old woman stays at home with her husband. The old man looks after his wife well and she 2 worries about anything. And she is very 3 . Just like some old people, Mrs. Black finds that her memory(记忆) is falling. Sometimes she 4 what she did or will do. It often gets her in trouble. Her 5 noticed（注意到） it and asked her to see a famous doctor. He bought two tickets 6 London and told her he put 7 into her handbag while she was playing the piano. The next morning, they got to the 8 just on time to catch the plane. Mrs. Black said,“I wish we had the 9 with us.” “Don’t be a fool, dear!”said Mr. Black,“We are not going to a concert, but to see a 10 .” “I know，”she said，“but I left the tickets on it!”
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