1min内电路消耗的电能为多少?
W=UIt=3V×0.2A×60s=36J
Don't stick your arm out of the window when the car is running; ________ you will be hurt． （ ）
黄土高原最主要自然灾害是（ ）
⑴is (过去式)____
⑵could not (缩写形式)____
⑶saw (原形)____
⑷give (过去式)____
