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问题 选择题
已知集合A={x|x≤
13
}，a=2
3
，那么下列关系正确的是（　　）
A．a⊆AB．a∈AC．a∉AD．{a}∈A
答案

∵集合A={x|x≤

13
}，a=2
3
，且2
3
=
12
＜
13
，

故a∈A，故B正确，C不正确；

对于A，元素与集合之间不能用符号“⊆”故错；

对于D，集合与集合之间不能用符号“∈”故错．

故选B．

填空题

用所给动词的正确形式完成短文，并将答案依次填在短文中相应的横线上。

Dear Zhang Lin ,

    How's it going? I    1    ( have ) some problems at school. I find it difficult to work in the evening and I can't concentrate on anything at the moment. I spend most of my time   2   ( listen) to records or watching TV instead of doing my homework. The other students in my class __3   ( be ) much better than me. I have the following problems as well.I can't always take down the important things my teacher   4   (say) , because I write too slowly. She   5   ( tell ) me that I'm falling behind my class mates in my studies. I'm not good at  _6   ( write )and I usually hand in my homework late because I won't do it until the last minute. So I often have to find different excuses _7   ( let ) my teacher know why I haven't done the homework. I'm sure I _8   ( get) through my final exam in January.I'm now so far behind the other students that I don't know how I can   9    ( catch ) up with them.Last week, when my teacher _10   ( help ) me with my homework , she. found so many mistakes , which made me more upset.

    Could you please give me some good suggestions?

                                                                                                                                      Yours ,

                                                                                                                                           Wei Hua
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