问题
单项选择题
半价层的大小与()因素有关。
A.管电压
B.管电流
C.物质的原子序数
D.物质的密度
答案
参考答案:B
半价层的大小与()因素有关。
A.管电压
B.管电流
C.物质的原子序数
D.物质的密度
参考答案:B
用适当的词填空。(共10小题;每小题1分,满分10分)
小题2:The boy knows much about the and differences between pop music and classical music. 小题3:The government is making efforts to ________the traffic noises in order to let citizens have a quiet sleep. 小题4: have been taken to reduce pollution in developing countries. 小题5:He threw it forward with all his . 小题6:The buses are so during the rush hour. 小题7:The polluted air and water can explain the main reason why the ________here are getting ill one by one. 小题8:Our goal is to reduce the number of the families in in the village. 小题9:An unexpected storm when we were enjoying the pleasant voyage at the Yellow Sea. 小题10:One million five hundred thousand people died in natural _____ between 1980 and 2000 |