We ' ll bring up the rear and keep an eye out for any surprises 要是你们收到了导航电波，就请以最大速度行进。我们将跟在后面保持警戒。
2.
The act of throwing consists of giving the maximum speed to the missile at the moment when it leaves the hand . the involves acceleration from a resting position 这一动作是在器械出手时给与它以最大速度构成的.这涉及到由起始姿势开始给以加速度的问题
