external door的用法和樣例：
例句
- And as Peter knocked at the door of the gate, a damsel came to hearken, named Rhoda.
彼得敲外門(mén)，有一個(gè)使女，名叫羅大出來(lái)探聽(tīng)。 - The outer door is a polyurethane foamy one with a glazing unit observation window, for better perspectivity and heat preservation.
外門(mén)為聚氨脂發(fā)泡門(mén)，中空玻璃觀(guān)察窗，透視性好，保溫性能好。
