_____ miss the train, our teacher had to
题型：选择题
问题：
_____ miss the train, our teacher had to get up very early this morning. [ ]
A. In order not to
B. So as to not
C.In order to not
D. So as not to
题型：选择题
如图所示，湖面上一点O不断地上下振动，形成以O点为圆心的圆形水波．某时刻O点处在波峰位置，经观察发现，2s后此波峰刚好传到距O点4m远处的A点，此时O点正通过平衡位置向下运动，OA间还有一个波峰，若水波近似为简谐波，则此水波的传播速度为______m/s，水波的波长为______m．
