问题 选择题

如图所示,杠杆A、B两端分别挂有体积相同、质量相同的空心铜球和空心铁球调节杠杆使其在水中保持平衡,然后小心地向烧杯中央滴入浓CuSO4溶液,一段时间后,下列有关杠杆的偏向判断正确的是(实验过程中不考虑铁丝反应及两边浮力的变化)                     

A.杠杆为导体和绝缘体时, 均为A端高B端低

B.杠杆为导体时,当溶解56g的铁时,杠杆中通过了3mol电子

C.当杠杆为绝缘体时,A端低B端高;为导体时,A端高B端低

D.当杠杆为绝缘体时,A端高B端低;为导体时,A端低B端高

答案

答案:D

铁和硫酸铜反应,当杠杆为绝缘体时,B端质量减小,A端增重。A端高B端低;为导体时,A端低B端高。

阅读理解

Zhang Li lies in bed sadly. The 24-year-old young man lost his right leg because of a blood disease. The doctor said that his 10 years of smoking had caused the disease. “I began to smoke when I was in Junior 3. It made me feel like a man and I thought it looked cool. Now I know I was really wrong.” said Zhang.

It is a mistake many teenagers make. It is said that about 40 million of the country’s young people between 13 and 18 have tried smoking. Nearly 68 percent of teenager smokers smoked their first one before the age of 13. Those who live in big cities started even earlier. Many teenagers see people smoking in the movies. But in real life, stars like Jackie Chan think smoking is a bad thing. In fact, smoking is one of the top killers in China. Each year one million people die from smoking-related(与吸烟有关的)diseases. Smoking causes illnesses like lung cancer and heart disease.

Doctors say that the younger a person starts smoking, the worse it will be. If a person starts smoking as a teenager, he or she may live twenty-two years less than non-smokers.

小题1:What kind of disease did smoking cause for Zhang Li?

A. Lung cancer.  B. Blood disease.   C. Heart disease.

小题2:From the passage, we know Zhang Li started to smoke when he was      years old.

A. 13 B. 14   C. 18

小题3: The city’s young people          .

A. knew that smoking was a bad thing

B. tried smoking when they were in Junior 3

C. started smoking earlier than those in the country

小题4:Which of the following is NOT TRUE according to the passage?

A. Zhang Li had a disease and lost his left leg.

B. Smoking may cause many kinds of diseases.

C. Smoking may make you have a shorter life.

小题5: What does the underlined word “non-smokers ” mean in English?

A. People who like smoking.

B. People who smoke.

C. People who don’t smoke.

判断题