问题 选择题

下列物态变化现象中,属于汽化吸热的是(  )

A.春天的早晨出现大雾

B.夏天洒水车洒在地面上的水变干

C.秋天的早晨花草上出现露珠

D.冬天早晨屋顶上有霜

答案

雾和露都是空气中的水蒸气遇冷液化成的小水珠,是液化,放热.霜是空气中的水蒸气遇冷直接凝华成的小冰晶,是凝华,放热.水变干是由液态变为气态,是汽化,吸热.

故选B.

填空题

阅读下面短文,用括号内所给动词的适当形式填空 (必要时可加情态动词或助动词)。

     I recently heard a story about a famous scientist. Because of his great achievements (成就), he was

thought to be more creative (有创造性的)than the average (一般的) person. When He (1) ____________

(ask) why he was able to do this, he gave the answer. It all came from an experience with his mother

when he was about two years old. "I (2) ____________ (try) to get a bottle of milk from the fridge when

I lost the bottle and it fell, spilling (溢出) the milk all over the floor-a sea of milk! I was frightened and I

didn't know what to do!" he said.

     His mother heard the noise and got into the kitchen. "I (3) ______________ (consider)how to explain

all this to you, mom." He said. Instead of (4) ____________ (punish) him, she said, "Robert, what a great

mess (杂乱) you have made! I (5) ____________ (not see) such a huge sea of milk before! Well, since

the milk has already been spilled, would you like (6) ____________ (play) in the milk for a while? We

(7) ____________ (clean) it up after that." Indeed, he did so. After a few minutes, his mother said, "You

know, Robert, whenever you (8) ____________ (make) a mess like this, finally you have to clean it up."

He used a sponge (海绵) and together they cleaned up the spilled milk.

     His mother then said, "You know, we (9) ____________(fail) in how to successfully carry a big milk

bottle with two tiny hands just now. Let's go out in the yard and fill the bottle with water to see if you

(10) ____________ (discover) a way to carry it." Then the little boy learned that if he grasped (抓紧) the

bottle at the top near the lip with both hands, he could carry it without dropping it.

     What a wonderful lesson!

单项选择题