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She inspected the carpet for small items. She saw a paper clip and a rubber band. She picked them up. She put them into a little box on the kitchen counter. She plugged in the vacuum cleaner. She turned on the switch. The cat ran out of the room. She
This is Scientific American 60-Second Science. I'm Cynthia Graber. This will just take a minute. The fridge is one of your home's biggest energy hogs. Better insulation can make refrigerators much more efficient. And a panel encasing a vacuum is one
今天要学的一个词是:pump。pump,Pump一般是指泵,或抽水机。可是今天讲的pump是指汽车加油站的泵。英国石油公司宣布停止在阿拉斯加的石油开采,《洛杉矶时报》的标题说:Oilfield Closure t
CAPE CANAVERAL Two American astronauts will venture outside the International Space Station Monday to stow a failed coolant pump and extend the outpost's Canadian railway. Wearing protective spacesuits in a deadly vacuum(真空) environment, Stephen
今天要学的一个词是:pump。pump,Pump一般是指泵,或抽水机。可是今天讲的pump是指汽车加油站的泵。英国石油公司宣布停止在阿拉斯加的石油开采,《洛杉矶时报》的标题说:Oilfield Closure t
Sit on a swing, let someone push you, and away you go. But what happens if the person who pushed you walks away, and you want to swing faster and higher. If you've ever been in the second grade, you know the solution to that. Just start pumping your