X型四轴前进时，其1、3号电机的动作应该是（）。
A.加速、加速
B.减速、减速
C.加速、减速
D.减速、加速
参考答案：D
- Can I take these magazines home?
- Yes, you ________ , but please return them in two days.[ ]
A) must
B) may
C) should
D) need
雾对飞行有哪些影响？
