瓶组供应系统supply system of cylinder group
参考答案：
配有2个以上15kg和2个或2个以上50kg气瓶的用户供应系统。
I don't know _______ he will come or not tomorrow. _______ he comes, I will tell you.
[ ]
A. if, Whether
B. whether, Whether
C. if, If
D. whether, If
57001--57998次列车是什么列车？57001--57998次列车是路用列车列车。
