若│-a│=5,则a=( )。
若3xm+5y2与x3yn是同类项,则m与n的值分别为( )
A.-2,2
B.2,-2
C.3,2
D.3,-2
If they spend some time on Chinese history, they will be more able to predict China''s future.
A.more
B.able
C.better
D.better able