多项式15m3n2+5m2n﹣20m2n3的公因式是( )
A:5mn
B:5m2n2
C:5m2n
D:5mn2
***曾称赞傅作义是“民族的功臣”“为和平解放各地战事问题和减轻人民的战争痛苦树立了榜样”.上述评价与哪次战役有关( )
——Your father never gets up late, does he?——______. It's unusual for him to be late for work this morning.
雷雨天闪电时空气中有臭氧(O3)生成.下列说法正确的是( )