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问题 选择题

水的净化知识在生活中有广泛应用，以下四种净化水的操作，净化程度相对较高的是（　　）

A．蒸馏

B．过滤

C．吸附

D．静置

答案

蒸馏是通过加热的方法使水沸腾变成水蒸气，然后冷凝成水的过程，是净化程度最高的一种方法；

故选A．

完形填空

首字母填空。（10分）

Three men were t__小题1:__ about the world’s greatest wonders.

The first man said,” I think the pyramids are the greatest. Though people b__小题2:__ them thousands of years ago, they are still standing. And just think: people at that time didn’t have our m__小题3:__ machines(机器). How could they build them so long ago?”

“I a__小题4:__ that the pyramids are wonderful.” The second man said. “ but I think computers are more wonderful. Everyone knows computers have changed the world a lot since people i__小题5:__ them.”

Then the t__小题6:__ man said, “ I d__小题7:__ with you two. I think the most wonderful thing is the thermos(热水瓶).”

The other two men were very s__小题8:__ , “ A thermos!” They said. “ Why? It’s a simple(简单) thing.”

“Oh, no,” the man said.” In w__小题9:__ you put in hot water and it stays hot. In summer you put in a cold drink and it stays cold. How does the thermos know w__小题10:__ it is winter or summer?”
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判断题

雷管测试仪使用完毕，应将转换开关放在“开”的位置。（）
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