—The newspaper said, “LiNa is on Time cover”.—____________exciting news it is!
A:What
B:How
C:What a
D:How a
—________ your sister often ________ sports?
—Yes,she often ________ tennis with my parents.
已知点A,B,C在圆x2+y2=1上运动,且AB⊥BC,若点P的坐标为(2,0),则PA→+PB→+PC→的最大值为( )
《颜氏家训》说中国古代能够“闭门而为生之具以足”,这说明