问题 问答题

一辆运载浓硫酸的槽罐车因交通事故翻倒在公路上,造成浓硫酸大量泄漏。因公路两旁都有农田,为使事故对环境造成的影响尽可能降低,提出了处理事故的三种措施,请你分别给予评价并选择其中的最佳措施。

(1)用大量水冲洗泄漏在公路上的浓硫酸。

(2)将生石灰撒在泄漏的浓硫酸上。

(3)用氢氧化钡撒布在泄漏的浓硫酸上。

答案

(1)用水冲洗所形成的稀硫酸将流入两旁的农田而造成强酸污染;    

(2)用生石灰可中和硫酸生成微溶于水的CaSO4,使硫酸对农田的污染得到较好的控制,且生石灰价格低廉、易得,是最佳的处置措施;    

(3)用氢氧化钡虽可中和硫酸生成难溶的BaSO4、降低硫酸的污染,但撒布的氢氧化钡过量会造成重金属污染,且氢氧化钡价格高,不易得到。

阅读理解

阅读理解。

     Mrs. Black is sixty-nine years old. She only has a daughter named Sandra. Mr. Black died twelve

years ago. Mrs. Black was very sad and lived in her house alone. Two years ago her daughter had a

baby. The young woman was busy all the time and had no time to look after her son James. She asked

her mother to live with them.

     The old woman had to sell her house and moved there. She was strong and could do all the

housework. And the family liked her.

      Last autumn Mrs. Black went to do some shopping. A car hit her and her leg was hurt. She had to

be in hospital for three months. She couldn't do anything after she came back. At first her daughter was

kind to her, but soon she began to be tired of (讨厌) her. The old woman wanted to leave, but she had

no money to buy a house and nobody could take care of her. She didn't know what to do.

      One morning Mrs. Black broke a plate. It made her daughter angry. She told James to buy a

wooden (木制的) plate for his grandma. That afternoon James came back with two wooden plates. She

was surprised and asked, "Why did you buy two plates, son?"

     "One is for grandma," answered the boy, "the other is for you! You will also have to use a wooden

plate when you're old, I think."

      The woman heard this and was sad. She cried for long. Now she is kind to her mother as she was

before.

1. Sandra asked her mother to live with them because ______.

A. the old woman lived alone

B. she needed her help

C. the old woman couldn't look after herself

D. the old woman could give her much money

2. The family liked Mrs. Black at first because ______.

A. she was very rich

B. she could watch their door

C. she could do all the housework for them

D. she was friendly to them all

3. Mrs. Black was afraid that ______, so she couldn't leave her daughter's house.

A. she had no house to live in

B. she couldn't look after herself

C. Sandra couldn't go to see her any more

D. A and B

4. James bought a wooden plate for his mother because ______.

A. he didn't love her

B. he liked it

C. he hoped she would be kind to his grandma

D. she often broke the plates at home

5. Sandra is friendly to her mother again because ______.

A. she knows she did wrong

B. she was afraid of her son

C. the old woman is poor

D. it's her duty

问答题