His only connection to the outside world was an air tube and a bell. Each day he rang a bell to let those outside know that he was still alive.

墓内的僧人和外界的一切联系只有一根输气管和一个铃铛，每天僧人都会摇铃使外面人知其还活着。

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While concentrations varied daily, typical concentrations of lead particles ranged from 0.6 to 1 microgram per cubic meter of air, Bell and her thesis adviser Catherine Cahill found.

Bell和她的论文导师Catherine Cahill发现，尽管浓度含量每天都发生变化，铅浓度含量一般在0.6到1微克每平方米空气之间。

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Because it needs air to work, we won't be using it to move spaceships any time soon, but Alexander Graham Bell didn't have "call waiting" or "text messaging."

牵引光束需要空气才能工作，所以短时间内还不能用它来发射宇宙飞船。 这也无可厚非因为万事开头难嘛，贝尔当时也不能呼叫等待和发短信啊。

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Chief executive of the air ambulance service Adrian Bell said he expected between one and four callouts across the four counties per night.

BBC: Dunsfold-based air ambulance to fly at night

The Colombian Air Force said that the Bell 212 helicopter was on a transportation mission from Barranquilla to Caucasia when it went down.

CNN: Colombian Air Force helicopter crashes, killing 13

Three cats climb to the top of the bell tower and sniff the air.

NEWYORKER: Town of Cats