A-A+
Obviously these are all factors affecting smoo
问题详情
Obviously these are all factors affecting smooth operation, but the underlying problem is still to be identified.
A．operational
B．fundamental
C．operating
D．underneath
参考答案
正确答案：B
解析：operational操作的；fundamental基础的，根本的；operating运行的，操作的；underneath下面的。
