油类杂质能（）树脂微孔，使这些微孔中的（）不能进行离子交换作用，从而降低树脂的交换容量。
参考答案：堵塞；活性基团
中国现有宜农荒地3500万公顷。( )
A. China now has 350 million hectares of wasteland which are suitable for fanning.B. China now has 35 million hectares of wasteland which are suitable for farming.C. China now has 3.5 million hectares of wasteland which are suitable for farming.D. China now has 35 billion hectares of wasteland which are suitable for farming.
班级管理
