土壤异常的形成机制主要有（）
A.氧化还原反应
B.矿物的溶解
C.电化学反应
D.机械分散
参考答案：A, B, C, D
—I don’t know what I _______ without the suitcase you lent me.
—Glad to have been of some help to you.
A．would have done
B．would do
C．should have done
D．should do
拆迁安置
