问题 选择题

鉴别下列各组物质的方法中,不正确的是(  )

A.用水鉴别氯化钙和碳酸钙

B.用闻气味的方法鉴别白酒和白醋

C.用稀盐酸鉴别黄金和黄铜(含锌)

D.用酚酞溶液鉴别氯化钠溶液和盐酸

答案

A、碳酸钙不溶于水,氯化钙溶于水,所以可以鉴别,正确.

B、白酒有醇香味,白醋有刺激性气味,所以闻气味可以鉴别,正确.

C、黄铜中含有锌,溶于盐酸后表面会失去光泽,并且可能有气泡产生,而黄金不会和盐酸反应,所以可以鉴别.

D、酚酞遇碱性溶液变红色,遇中性和酸性溶液没有明显变化,氯化钠溶液为中性溶液,盐酸为酸性溶液,所以没法鉴别.

故选D

阅读理解

阅读理解。

     There are many wetlands in China and some of them have become the world’s important wetlands.

The Chinese Yellow Sea Wetlands are among them. They are in Yancheng, Jiangsu Province. They are

home for many different kinds of animals. The world’s largest Milu Deer Nature Reserve is in them. More

than 700 Milu deer live freely there.There are not many red-crowned cranes in the world,but every winter you can see some in the Red-crowned Crane Nature Reserve in the Yellow Sea Wetlands.

    The temperature in the wetlands is usully neither too high nor too low.There us a lot of rain and sunshine

,  too. They are really good places for wildlife. Offering(提供) food and home for some special kinds of

animals is not  the only reason why we need to protect wetlands. Wetlands are important because they

also prevent flood. But some people want to change the wetlands to make more space for farms and less

space for wildlife.

     Luckily , more and more people are beginning to realize the importance of wetlands and wildlife.Every year , on February 2nd , many activities are held to tell people more about wetlands.

1. The Chinese Yellow Sea Wetlands are in the _______of China.

A. east      

B. south    

C. west    

D. north

2. Usually the weather in the wetlands is _______

A. hot      

B. pleasant    

C. cold    

D. dry

3. The World Wetlands Day is  on _______

A. April 22      

B. June 25    

C. February 2  

D. March 22

4. We must protect wetlands because _______

A. they are home for wildlife  

B. they can offer food to animals

C. they can prevent flood      

D. all of the above

5. Some people want to change _______ to make more space for farms 

A. lands    

B. world      

C. wildlife    

D. wetlands

选择题