A:质量比为1:9的H2和O2
B:质量比为3:6的C和O2
C:质量比为1:6的CH4和O2
D:质量比为7:2的CO和O2
—How far is it from Beijing to Haikou?
—It's a______ flight from Beijing to Haikou.
如图,平行金属板A、B水平正对放置,分别带等量异种电荷,一带电微粒水平射入板间,在重力和电场力共同作用下运动,轨迹如图中虚线所示,那么( )
查字典
“睦”按部首查字法应查____部,再查____画,组词____