当要求内部关闭时，这些应包括通风系统进口和出口的关闭装置。

When internal closing is required, this should include both ventilation intakes and outlets.

youdao

当要求内部关闭时，这些应包括通风系统进口和出口的关闭装置。

When internal closing is required, this should include both ventilation intakes and outlets.

youdao