问题 选择题

2013年扬州4.18晚会现场将采用LED节能光源,GaP(磷化镓)是光源材料,其中Ga为+3价,则P元素的化合价为

A.﹣3

B.﹣5

C.+3

D.+5

答案

答案:A

题目分析:在GaP中,已知Ga元素的化合价为+3价,设该物质中P元素的化合价为x价,根据GaP的化学式和化合物中正负化合价的代数和为0的原则,则有(+3)+x=0,解得x=-3。故选A

点评:本题考查元素化合价的计算,正确利用化学式和常见元素的化合价,结合化合价的计算原则“在化合物中,正负化合价的代数和为0”来计算即可。

阅读理解

根据短文内容回答下列问题,每空一词。

  It was a Saturday afternoon. Mr Green was reading a newspaper when he

heard his wife crying in the next room. He hurried to her and asked, "What

happened to you, my dear?"

  "Oh,dear!" his wife called out. "My head hurts! Send for a docto. Hurry up!"

Their two children were both out at that moment and something was wrong with

the telephone. Mr Green had to go to a hospital himself . Bad luck! That day all

the hospitals in the town were closed. Mr Green didn't know where to go. Just

then a friend of his saw him and asked,"What is the matter?"

  Mr Green told his friend. The man said,"Why not go to Mr Black? He can

help you. "

  Mr Green was told by his friend Mr Black was a good doctor. He hurried to

Mr Black. When he got there, Mr and Mrs Black were having their evening meal.

The doctor asked Mr Green to drink with him. He was happy and sat at the table.

After that they began to chat(聊天). And when Mrs Black asked," How is your

wife?" "She is fine,thank..."Mr Green stopped at once-he remembered his wife

was waiting for a doctor at home.

1. What was wrong with Mrs Green on a Saturday afternoon?

She had _____ a _____.

2. What did Mrs Green want her husband to do?

She wanted him to _____ a _____ to come at once.

3. Who helped Mr Green when he didn't know where to go?

One of _____.

4. When did Mr Green think of his wife?

He _____ think of his wife _____ Mrs Black asked him how his wife was.

5. What was Mr Green like?

He was a _____.

6. 文中画线的句子用的是什么时态?

                                                                            

7. 将文中画线的句子译成汉语。

                                                                            

单项选择题 B型题