A:除去CO2中的CO(灼热的CuO)
B:除去O2中的H2O蒸汽(CaO)
C:除去NaCl溶液中的Na2CO3(CaCl2溶液)
D:除去C粉中的Cu粉(稀硫酸)
(____) I'm looking out of the window.
(____) Some children are making a snowman.
(____) In this photo,we are in the mountains.
(____) The wind is blowing and the sun is shining.
(____) I am having a lovely time.
如图所示,能表示点到直线的距离的线段有 ( )
如图所示,重为G的物体静止在倾角为α的粗糙斜面体上,现使斜面体向右做匀速直线运动,通过的位移为x,物体相对斜面体一直保持静止,则在这个过程中( )