A:KBr
B:NaOH
C:HBr
D:N2
- What's in the classroom? ( )
- Two doors and _____ chairs.
-----I'm waiting for the mail. Do you know it will arrive?
-----Usually it comes by 4:00 p.m.
下列现象不属于大气对太阳辐射削弱作用的是( )
请根据下面的统计图回答下列问题.
下列动物中不具有社会行为的是( )