问题 解答题

如果你要探究“蚯蚓在什么样的物体表面爬得快?”,你会准备哪些实验材料?______.

答案

蚯蚓属于环节动物,没有骨骼,蚯蚓的运动就是依靠纵、环肌的交互舒缩及体表的刚毛的配合而完成的.当蚯蚓前进时,身体后部的刚毛钉人士内不动,这时环肌收缩,纵肌舒张,身体就向前伸,接着身体前端的刚毛钉入土内不动,这时纵肌收缩、环肌舒张,身体向前缩短而前进.收缩舒张交替进行,从而使蚯蚓向前蠕动.

生物探究实验以对照试验为主,因此.试验中可以先让蚯蚓在光滑的玻璃上运动,然后在把蚯蚓放在粗糙的硬纸板上运动,对照观察.在光滑的玻璃上,刚毛无法固定和支撑身体,在粗糙的硬纸上刚毛能起到固定和支撑作用,因此蚯蚓在粗糙纸面上的运动速度比它在光滑的玻璃板上的运动速度要快.蚯蚓是用湿润的体壁进行呼吸的,因此试验过程中用浸过水的棉球轻擦蚯蚓体表,可以使体壁保持湿润,维持蚯蚓的正常呼吸.故本实验需要:活的蚯蚓、粗糙的硬纸板、光滑的玻璃、湿棉球(或湿棉花).

故答案为:在粗糙纸面上爬得快;活的蚯蚓、粗糙的硬纸板、光滑的玻璃、湿棉球.

阅读理解

阅读理解。

     Mr. Reece was a farmer. He and his wife grew a lot of things. They worked very hard. One day,

Mr. Reece said to his wife, "Let's go to the city next Sunday. We can have a good lunch there, and

then we'll go to the cinema."

     His wife was very happy when she heard this, because she and her husband always ate a lot. She

didn't like cooking three times a day.

     They went to the city by train the next Sunday. They walked about for an hour. When it was twelve

o'clock, they wanted to have a meal. They looked at some restaurants. They saw a notice (布告), "Lunch

12:30 to 2:30, 1.5 dollars."

      "Well, that's good," said Mr. Reece, "we can eat for two hours for 1.5 dollars here. That's too cheap. This is the place for us."

1. Mr. Reece usually worked in ______.

A. the fields  

B. the city  

C. the restaurant 

D. the theatre

2. Mr. Reece and his wife went to the city ______.

A. to have a good lunch    

B. to see a film

C. to do some shopping    

D. A and B, maybe C, too

3. When did Mr. and Mrs. Reece arrive in the city?

A. At about 11:00.    

B. At about 12:00.

C. At about 12:30.    

D. At about 2:30.

4. We can see that Mr. Reece ______.

A. was poor              

B. was rich  

C. understood the notice    

D. didn't understand the notice

5. Why did Mr. Reece say that restaurant was the place for them? Because ______.

A. that was the best restaurant

B. 12:30 to 2:30 was the best time for lunch

C. he thought they could eat a lot and it was cheap

D. they were very tired and hungry    

多项选择题