(2015.•广东佛山)I don't understand why more girls ________ to do housework than boys in today's society.
A:asked
B:were asked
C:are asked
A,B两物体沿直线运动的V﹣t图象如图所示,下列说法中不正确的是( )
我国下列地区被外国殖民势力占据时间最长的是