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【简答题】
条形码可以分为 _________和 _________条形码。
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皮皮学刷刷变学霸
举一反三
【单选题】The earth is much cooler than the sun, and the wave length of the earth's radiations is much longer than that of sunrays. These longer heat waves cannot pass through the atmosphere as easily as the sh...
A.
heat waves rising from the earth
B.
waves absorbed by water vapor
C.
waves sent out by radio stations that transmit local programs
D.
the rays sent out from the sun
【简答题】accomplish
【简答题】accomplish
【单选题】How could 'levels of electromagnetic radiation that exceed international safety standards' be produced?
A.
Mobile phones give off a lot of electromagnetic radiation.
B.
Train carriages, buses, and lifts are not safe places to use mobile phones.
C.
A lot of people could use their mobile phones in a confined space at the same time.
D.
Blathering produces radio waves which bounce around the interior of these places.
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