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问题 问答题

何谓经济效益临界？判断其标准是什么？

答案

参考答案：经济效益临界是指在分析技术开发、产品生产和项目建设等经济活动中有没有效益，以及取得效益的临界值。这里有两种情况：第一、经济效益临界就是在经济上能否取得收益的数量界限，只有具体数值表明所得大于或等于投入时，才能真正获得经济效益。其表达式为： 经济效益临界＝所得－所费（或收入－投入）≥0 →最大 或所得∕所费（或收入∕投入）≥1 →最大第二、以被选择方案的机会成本来确定经济临界，其表达式为： 经济效益临界＝被选择方案的经济效益－机会成本≥0 →最大式中的机会成本系指方案选优中假定未被选方案所损失的利益。（每种情况2 分）

改错题

下文中共有10处语言错误。请在有错误的地方增加、删除或修改某个单词。

增加：在缺词处加一个漏字符号（∧），并在其下面写出该加的词。

删除：把多余的词用斜线(\)划掉。

修改：在错的词下划一横线，并在该词下面写出修改后的词。

注意：1．每句不超过两个错误；

2．每处错误及其修改均仅限一词；

3．只允许修改10处，多者（从第11处起）不计分。

Three weeks ago I bought the electronic dictionary at a shop. But I hadn't used it for several day while I found it didn't work. So I went to the shop, but only to be told that the problem could not be solved unless it was sent back the factory where it was made .Then I did as I was told without any delay. Unfortunately, the factory promised to repair the dictionary and sent it back in a week. Two weeks has past, but I haven't yet received one. l have no idea ,why things are like this. I'm looking forward to receive my dictionary as soon as possible.
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填空题

根据句意填空，每空一词。

1.  John is late for class again.  The teacher is a ______ with him.

2.  -I have a bad cold, doctor.

     -Well, take the ______ three times a day.

3.  My grandfather is very strong but my grandmother is w______.

4.  You shouldn't be a ______ with your mother at this small thing.

5.  We all know the sun rises<升起) in the e______ and sets (落下) in the w

6.  One of his ______ is sore.  He can't walk now.

7.  In our school, e______ wears uniforms.

8.  In winter, it g______ shorter and shorter.

9.  China is to the e______of Japan.,

10.  He has ______ friends here, because he is new.

11.  The shirt is ______. (有点) expensive, I can't afford it.
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