社会生活的方方面面都不能缺少人与人的沟通、互助、合作,和谐的人际关系是人人渴望的,建立和谐的人际关系必须由_____ 开始 ( )
A:理解
B:自尊
C:奉献
D:自信
甲物质的密度为5g/cm3,乙物质密度为2g/cm3,各取一定质量混合后密度为3g/cm3.假设混合前后总体积保持不变,则所取甲、乙两种物质的质量之比是( )
—How was your climbing Mount. Huang?
—I didn't believe I could do it ___________ I got to the top.