地球内部圈层的划分依据是[ ]
A.地震发生时的地面变化
B.通过打深井而获得的信息
C.由地震波的传播速度变化而形成的不连续界面
D.通过卫星遥感技术获得的信息
答案:C
-Why do you stay at home this evening?
-Because I have __________ homework to do.[ ]
A. too much
B. much too
C. too many
矿物中绝大部分是固体,少数是液体和气体。