无论在什么情况下,进食含糖食物后,蛀牙便会迅速形成。( )
在甲、乙两图中,甲图地面粗糙、乙图地面光滑。质量分别为m, 2m的两个物体在大小为F的恒力作用下,在力的方向上前进了相同的距离,则下列结论正确的是( )
— Talking loudly in a library is impolite.
— In fact, we should also ________ not to cough(咳嗽) or sneeze(打喷嚏)loudly in public.