【简答题】In all countries, employment in this activity never went beyond 1%.
【单选题】( )的工频电流通过人体时,人体尚可摆脱,称为摆脱电流。 A、0.1mA B、2mA C、4mA D、10mA
【单选题】阅读材料,回答题。 We all know that it is possible for ordinary people to make their homes on the equator (赤道), although often they may feel uncomfortably hot there. Millions do it. But as for the NorthPole (北...
A.
feeling uncomfortably hot on the equator
B.
flying over the North Pole
C.
flying over the equator
D.
making homes on the equator
【单选题】In order to solve the problem of global warming, all countries should ______.
A.
replace all the harmful substances
B.
make progress in economy development
C.
share ideas and bear common responsibilities
D.
develop advanced technology to improve the situation
【多选题】压电式加速度传感器参数中有( )灵敏度( )灵敏度( )灵敏度。
【单选题】( )的工频电流通过人体时,就会有生命危险。 A、0.1mA B、1mA C、15mA D、50mA
【单选题】They do eye exercises twice a day , so ____of them ____glasses.