The dog _______ played with you just now is _______.
A:which; mine
B:which; my
C:what; mine
D:what; my
关于电流方向下面说法正确的是 ( )
写出下列烃的分子式:
(1)辛烷 ____
(2)乙烯 ____ ;
(3)含有30个氢原子的烷 ____ .
(4)假如某烷烃的相对分子质量为142,则该烷烃的分子式为 ____