dangerous /?de?nd??r?s/ adj. 危险的，不安全的
锁门 lock the door
A：Lock the door if you're the last one to leave.
如果你最后一个离开，就把门锁好。
B：Set your heart at ease about it.
这件事你就放心吧。
◆ at ease 放心，安心，自在
（用门闩）把门闩上 bolt the door
A：The old woman bolts the door at dusk every day.
每天傍晚的时候，那个老太太都要把门闩上。
B：Around here, it's dangerous to leave the door open after sunset.
在这附近，日落后还开着门是很危险的。
bolt /b??lt/ v. 用门闩闩（门） n. 门闩
dusk /d?sk/ n. 黄昏；薄暮
敲门 knock at/on the door
A：Listen! Someone is knocking at the door.