Chapter II analyzes the backwash of test to ELT classroom, Chapter III introduces continuous assessment.
第二章着重分析了考试对英语课堂教学得反作用。

Then the airwater backwash filter is adopted to perform grade III deep treatment to the Grade II effluent.
采用气水反冲洗滤池工艺对二级出水进行三级深度处理

Judging from the changes of head loss in the constructed intensified biological bed, it is known that the period time for backwash is120 days.
通过研究滤床水头损失变化，得出反冲洗周期为120天。