（）是巷道式通风的关键之一，为此必须做到：不做运输的横通道应及时关闭，以减少风流损失。
参考答案：挡风门
— I am so sorry to have come late for the meeting.
— It is not your fault. With ________ rushhour traffic and ________ heavy rain, it is no wonder you were late. [ ]
A. a; a
B. the; the
C. /; /
D. /; a
中国电信的外包服务、专业服务和知识服务均是（），是（）的服务。
