在施工作业半定量评价法：D=L×E×C中E等于“7”代表的是（）。
A、每天工作时间暴露
B、每天一次暴露
C、每周一次暴露
D、每月一次暴露
参考答案：C
He will have learned English for eight years by the time he ______ from the university next year.[ ]
A. will graduate
B. will have graduated
C. graduates
D. is to graduate
什么叫厂用电和厂用电系统？
