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问题 选择题

下列化学用语表示错误的是(   )

A．羟基电子式H

B．中子数为14的硅原子

C．镁离子结构示意图

D．甲烷的分子模型

答案

答案：C

Mg元素的核内质子数为12，Mg原子失去两个电子变成离子，质子数没变。

完形填空

根据对话内容，从方框内的选项中选出能填入空白处的最佳选项。选项中有两项为多余选项。

A:     小题1:   ?

B: I want to buy a miracle.

A:     小题2:  ?

B: It’s for my little brother. He has something bad growing inside his head. My daddy said only a miracle could save him.    小题3:   ?

A: How much do you have with you?

B: Two dollars and twelve cents. If it’s not enough, I can get some more later.    小题4:  .

A: What kind of miracle does your brother need?

B:    小题5: . He needs an operation. But my daddy can’t pay for it. So I’ve brought all my savings to buy a miracle to save him.

A: Ok, little girl. It’s the exact price of a miracle for your brother. Leave your address and the miracle will be delivered to your house.

(Some days later, enough money was raised to help the family. The operation was done and the little girl’s brother was saved. So how much is a miracle? It’s two dollars and twelve cents plus faith and love. )
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单项选择题

背光补偿是指可以使摄像机在（）下拍摄画面时，使输出视频信号的幅值提高，从而使监视器上的主体画面明朗、可视性得到改善的功能。

A.逆光环境

B.侧光环境

C.顺光环境

D.无光环境
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