急性脊髓炎的临床表现包括下列哪项（） A.截瘫 B.某平面以下各种感觉障碍 C.大、

     Jimmy is very   1   at Maths.
     Mary, his sister, doesn't do well   2   it. Jimmy often helps her with her Maths. One night Jimmy
and Mary took out their exercise-books and began   3   their lessons. Soon Jimmy finished   4   his
homework, but his sister   5  . She couldn't work   6   the last(问题). "Let me   7   you," said Jimmy.
"No, please   8  . I'll do it myself, " said Mary. She thought hard, an hour   9  , she worked it out. She
was very tired, but very, very   10  .