A facemask is a loose-fitting, disposable device that creates a physical barrier between the mouth and nose of the wearer and potential contaminants in the immediate environment.

• 答：外科口罩与脸的配合是宽松式的，作为一个物理屏障，它可以将使用者的口和鼻与外面的可能的污染空气进行隔离。