—Why don't you buy the bike, Mary? — It's too expensive. I can't it.
A:sell
B:lend
C:keep
D:afford
下列说法中正确的是( )
回答下列问题:
氧气是空气的主要成分之一,下列有关氧气的说法正确的是( )
2014年初,我国多地又陷入严重雾霾之中,被网友戏称十里“霾”伏,引起全社会高度关注。读下图,完成下列各题。