卫星通信中,通信线路的建立和控制非常简便的信道分配方式是()
A.固定预分配方式
B.全可变方式
C.随机分配方式
参考答案:A
---I’m sorry! I would have taken him to hospital if I had known he was seriously ill.
--- But ______ .
A.you didn't
B.you hadn't
C.he wasn't
D.you aren't
箱体零件外形复杂,对尺寸和形状、精度有较高的要求。