下列关于质量相同的CO和CO2的叙述正确的是( )
A.氧元素的质量比为11:4
B.氧原子的个数比为1:2
C.碳元素的质量比为1:1
D.分子个数比是11:7
答案:D
--- Does it rain a lot in this area?
--- , it hardly ever rains; the climate is like that of a desert.
A.What’s more
B.In other words
C.On the contrary
D.As a result
直放站有以下几种作用()
A.盲区覆盖
B.话务分流
C.系统扩容
D.提高基站设备利用率