硫醇钠盐是一种易溶于碱液和水,但不溶于液态烃的物质。
参考答案:对
Good news! The price of all those second-hand goods is ________ before.
A.30% as lower as
B.30% lower than
C.lower 30% than
D.as 30% low as
在实体属性中,可用于区别实体集合中不同个体的那个属性或几个属性的组合,称 【13】 。