在“小苏打、氮气、食盐、生石灰、二氧化硫、聚苯乙烯”中选择适_爱下问搜题

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问题问答题

在“小苏打、氮气、食盐、生石灰、二氧化硫、聚苯乙烯”中选择适当的物质填空：

（1）可用制灯饰外壳的是______；（2）溶于雨水后易形成酸雨的是______；

（3）可作食品干燥剂的是______；（4）焊接金属时常用作保护气的是______；

（5）可用于焙制糕点的是______；（6）可用作调味剂、防腐剂的是______．

答案

（1）聚苯乙烯是一种热固性塑料，可用来作灯饰外壳材料；

（2）二氧化硫、二氧化氮等气体能和水反应生成显酸性的物质，是形成酸雨的主要物质；

（3）生石灰能吸收水蒸气，常用作食品的干燥剂；

（4）由于氮气化学性质稳定，常用作金属焊接时的保护气；

（5）小苏打是碳酸氢钠，能和面发酵后形成的酸反应生成二氧化碳，使食品疏松多孔，可用于焙制糕点；

（6）食盐有咸味，无毒，生活中常做调味品；

故答案为：（1）聚苯乙烯；（2）二氧化硫；（3）生石灰；（4）氮气；（5）小苏打；（6）食盐．

完形填空

There was once a famous king whose name was Tamerlane. Like Alexander the Great, he _36__ to become the master of the whole world. So he raised a great _37__ and made war on other countries. He conquered(征服，打败） many kings and __38__ many cities. But at last his army was beaten; and Tamerlane escaped alone from the field of __39__ .
For a long time he wandered in __40__ from place to place. His enemies were __41__ him. He was about to lose all hope.
One day he was __42__ under a tree, thinking of his failure. He had now been a wanderer for twenty days. He couldn’t __43___ any longer. Suddenly he saw a small object climbing up the trunk (树干) of the tree. He looked more __44__ and saw it was an ant, __45__ a grain of wheat（麦粒）as large as itself.
There was a __46__ in the tree only a little way above, and that was the home of the ant.
“You are __47__, Mr. Ant,” he said, “but you are carrying something that is too heavy for you.” Just as he __48__, the ant lost its footing and fell to the ground. But it __49__ held on to the grain of wheat. Tamerlane _50__ the little insect. It tried the second time, the third time ... the twentieth time — but always with the same __51__. Then it tried the twenty-first time. __52__, one little step at a time, it climbed across the rough place where it had __53__ so often. The next minute it climbed __54__ into its home, carrying the grain of wheat. “Well done!” said Tamerlane, “you’ve taught me a lesson. I, too, will try, try again, __55__ I succeed.”
And this he did.

A．fighting against

B．looking for

C．caring about

C．discovering

单项选择题

按照一定的目的、任务和形式编制起来的社会集团，为了达到一个共同目标，在统一领导下分工合作的行为是（）

A.组织

B.集团

C.团体

D.联合体