A. Yes. Hold on, please.
B. Sorry, we are busy.
C. I am washing my clothes.
D. Hi, Danny.
E. It is Sunday today.
We walked back about two____(千米)and found Sam at last.
过正方体中有公共顶点的三条棱的中点切出一个平面,形成如图几何体,其正确展开图为( )
四位同学在一起讨论某种物质,请根据他们的讨论判断该物质是( )