使用氟化物是世界上公认的有效防龋方法,为确保氟化饮水的安全性,氟牙症指数为多少时,饮水中不需要加氟()
A.0.2
B.0.3
C.0.4
D.0.5
E.0.6
参考答案:E
根据句意,补全单词。
1. The boy wants his father to buy a _____ plane for him as a birthday present.
2. We often play games or go fishing in our _____ time after school.
3. We know Obama is the youngest _____ of the American.
4. Good _____ can help you find good job.
5. There are some _____ in the space such as the earth, the sun and so on.
计算机中之所以需要编译程序,是因为需要
A.将人的自然语言翻译成计算机语言
B.将汇编语言程序翻译成目标程序
C.将高级语言程序翻译成目标程序
D.人机对话