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问题 选择题

下表为元素周期表前四周期的一部分，下列有关表中各元素的叙述正确的是（　　）

②④
①③⑤⑥
⑦

A．原子半径的大小顺序是①＞②＞③＞④

B．氢化物的沸点：⑤高于④

C．氢化物的稳定性：⑦比⑥强

D．最高价氧化物对应水化物的酸性：②比③强

答案

A、同一周期元素的原子半径随着原子序数的增大而减小；同一族，元素的原子半径随着原子序数的增大而增大，所以原子半径的大小顺序是①＞③＞②＞④，故A错误．

B、同一族元素氢化物的沸点随着相对分子质量的增大而增大，但因水、氟化氢、氨气中含有氢键，所以水的沸点大于硫化氢的，氟化氢的沸点大于氯化氢的，氨气的沸点大于磷化氢的；如果该主族为第ⅣA族，氢化物的沸点：⑤高于④；如果该主族属于第ⅤA族或第ⅥA，氢化物的沸点：④高于⑤，故B错误．

C、同一族元素氢化物的稳定性随着元素的原子序数的增大而减小，所以氢化物的稳定性：⑥比强⑦，故C错误．

D、同一主族元素的最高价氧化物对应水化物的酸性随着原子序数的增大而减小，所以最高价氧化物对应水化物的酸性：②比③强，故D正确．

故选D．

单项选择题

I first went to hear a live rock concert when I was eight years old. My brother and his friends were all fans of a heavy metal group called Black Wednesday. When they discovered that Black Wednesday were going to perform at our local theatre, they all bought (21) for the performance. However, at the last minute, once of the friends couldn’t go, so my brother offered me the ticket. I was really excited!

I remember the buzz (嘈杂声) of excitement inside the theatre as we all found our seats. After a few minutes, the lights went down and everybody became quiet. I could barely make out the stage in the (22) . We waited. Then there was a roar from the crowd, like an explosion, as the first members of the band stepped onto the stage. My brother leaned over and shouted something in my ear, but I couldn’t hear what he was saying. The first song was already starting and the music was as (23) as a jet engine. I could (24) the drum beats and bass notes in my stomach.

I can’t recall any of the songs that the band played. I just (25) that I really enjoyed the show and didn’t want it to (26) . But in the end, after three encores (加演), the show finished. We left the (27) and walked unsteadily out onto the pavement. I felt a little dizzy, as if I had just woken from a long sleep. My ears were still (28) with the beat of the last song.

After the (29) , I became a Black Wednesday fan too for a few years before getting into other kinds of music. Once in a while, though, I listen to one of their songs and (30) I’m back at that first show.

30（）

A.decide 

B.regret 

C.conclude 

D.imagine
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判断题

关键事件技术是通过设计一定的表格，专门记录工作者工作过程中那些特别有效(成功)与特别无效(失败)的工作行为，作为将来确定任职资格的一种依据。()
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