A:风俗画
B:宫廷画
C:山水画
D:文人画
— Listen! Someone is knocking at the door. Who can it be?
— It _______ be Tom. He said he would visit me this evening.
已知m、n是两条不重合的直线,α、β是两个不重合的平面,下列命题中正确的是( )
下列分式是最简分式的是( )