— Let's ________ football this afternoon.
— Sorry, I like going __________.
A:play, swimming
B:play, swim
C:playing, swim
D:playing, swimming
平面内与两定点距离之比为定值 的点的轨迹是____.
“一个人可以没文凭,但不可以没知识;可以不进大学殿堂,但不可以不学习。”这表明,终身学习是( )