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问题 单项选择题

原子核衰变主要取决于（）

A.环境温度升高

B.环境温度降低

C.核内质子和中子数的比率及核能态

D.大气压

E.环境的pH值

答案

参考答案：C

解析：原子核的衰变主要与核内质子或中子相对过剩，及核能态有关。

改错题

假定英语课上老师要求同桌之间交换修改作文，请你修改你同桌写的以下作文。文中共有10语言错误，每句中最多有两处。没处错误仅涉及一个单词的增加，删除或修改。

增加：在缺词处加一个漏字符号（∧),并在其下写出该加的词。

删除：吧多余的词用斜线（\）划掉。

修改：在错的词下面画一横线，并在该词下面写出修改后的词。

注意：1.没处错误及其修改仅限一词；

2.只允许修改10处，多者（从第11处起）不计分。

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Comparing with other teachers, Mr Mike pays much attention to his way of teaching. He tries various ways to make his class lively and interested. In his opinion, we should not only know “what”, but also understand “why”. So, instead of giving us answers immediate, he encourages us to think by myself whenever he puts forward questions. Without his help, we've learned how to analyze and settle problems. What wonderful world of “ why” he leads us to !

He is such a learned person that we all admire him very much.
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单项选择题

鱼尾板尺寸长度允许偏差为（）。

A.+4，-4

B.+2，-2

C.+4，0

D.+4，-2
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