You are in black bear country. On cycling and walking trails, sing or ring your bell before bends to avoid surprising one.

你已经来到黑熊之乡，在自行车道或者步道上行进时，请在进入弯道前唱歌或打铃，以避免与动物不期而遇。

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The door bell or your mobile will always ring when you are in the bathroom.

门铃或你的手机总会当你在浴室时响起。

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Angel on the doorstep... make some cookies, put some in a cute little package, put them on the doorstep of your neighbor's house, ring the bell!

门阶上的天使…亲手烤制小饼干，将小饼干可爱地包扎起来，然后悄悄放到邻居家的门前台阶上。摇响手中的铃铛……然后逃跑！

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You waited for the door-to-door salesmen to ring your bell.

FORBES: A Foot in the Door No More

But if a family is concerned, when you're actually trick-or-treating, if you watch your child go to someone's door, ring the bell, and the other family comes to the door and hands them candy, it's one way of knowing it's a safe and comfortable gift of the candy.

CNN: Kate Kelly: Halloween safety