假如要给地球缝制一件外衣,那么所需的布料应不少于( )
A:5.1亿平方千米
B:5.1亿千米
C:5.1亿立方千米
D:5.11平方千米
算式 18÷3中,要使商的末尾是0, 里可以填____。
① How much cheese do you want ? ____ A. They will come tomorrow.
② How many things are there ? ____ B. I'm shopping .
③ When will these things come ? ____ C. Half a kilo.
④What are you doing ? ____ D. Thirty-seven.
如图所示,两板间距为d的平行板电容器与一电源连接,开关S闭合,电容器两板间的一质量为m,带电荷量为q的微粒静止不动,下列说法中正确的是( )