下列说法正确的是（ ）
A．水结成冰后，分子间的作用力减小
B．扩散现象只发生在气体、液体之间
C．对人体安全的电压是36V
D．一个电子所带的电荷量为1.9×10－16C
A
题目分析：水结冰后，由液体变成固体，体积变大，分子间的距离变远，分子间的作用力变小。扩散现象能发生在一切固体液体和气体之间。对人体的安全电压是不高于36V. 一个电子所带的电荷量为1.6×10－19C
选项A正确。
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| Bill is fifteen now, but he's still in Grade One. He likes 1 and does not like to use his 2 .He does not listen to the teachers in class and so he 3 his homework His teachers do not like him They tell his parents about it, but they do not 4_ what to do. It s Sunday today. Bill _5_ early in the morning. After breakfast, his mother tells him to do his 6_. He goes to his study. His mother is 7 with her housework. Bill goes out with a ball. Now lunch is ready, but she 8 Bill. When Bill comes back, his parents look very angry, but say nothing. After lunch Bill wants to go out again. His father stops him and asks, "Have you finished your homework? " "No,"answers the boy, "I can't do 9 ." His father pulls( 拉 ) him by the ear ana says," 10 your ear? " "Oh,dear! " Bill calls out ,"It's in your hand! | |||
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