A:x2+5x﹣6
B:x2﹣5x﹣6
C:x2﹣5x+6
D:x2+5x+6
如图所示,是常见的交通标志牌,其中与声现象有关的是( )
find out, feel like, quite a few, bring out, come out, of course, at least, make up, care about, dress up
两球相向运动,发生正碰,弹性碰撞后两球均静止,于是可以判定,在弹性碰撞以前两球()
____ they____ to go swimming in summer?