-- It's said that an airport _______ in Yangzhou.
-- It's true. That's what we are getting excited about these days.
A:builds
B:will build
C:is building
D:will be built
照样子,用两种计时法写出钟面上显示的时间.
用控制变量法,可以研究影响平行板电容器电容的因素(如图所示).设两极板正对面积为S,极板间的距离为d,静电计指针偏角为θ.实验中,极板所带电荷量不变,若( )
已知F1=3N,F2=5N,那么它们的合力大小不可能是