方程两边同时______或者______相同的数(0除外),左右两边仍然相等.
方程两边同时乘或者除以相同的数(0除外),左右两边仍然相等.
故答案为:乘,除以.
按发生机理,土壤自净可分为不同类型,其中不含()
A.物理净化
B.空气净化
C.生物净化
D.化学净化
—How do you like the book ?
—______[ ]
A. It's interesting.
B. What about you?
C. No,I don't like it at all.
D. I'd like to read it tomorrow