【单选题】In this part of the country, the evergreens rarely experience any ______ to growth through cold.
【简答题】A.Not use any electric appliances any more. B.Take part in a basketball final. C.Ask his neighbor to check the power. D.Watch a ball on television.
【单选题】( )we are ---- at what he said .what he sad is ----- .
【单选题】某阳离子X2+上网核外电子是18,中子数是20,则其质量数是( )
【简答题】A.Not use any electric appliances any more. B.Take part in a basketball final. C.Ask his neighbor to check the power. D.Watch a ball television.
【判断题】处于静电平衡的实心导体内部,电场强度处处为零