【单选题】— What were you doing when I rang you yesterday afternoon? — I was occupied ______ the housework and kept my daughter occupied ______ her homework. [ ]
【单选题】— I rang you at about nine, but there was no reply. — Oh, that was probably _____I was seeing the doctor.
【多选题】按照除菌方式的不同,可以将啤酒分为哪些类型?()
【简答题】( )的作用只是改变传动方向并不能改变传动比。
【单选题】— I rang you at about nine, But there was no reply. — Oh, that was probably ______ I was seeing the doctor. [ ]
【单选题】I was not at home when you ______ me.
【单选题】从本质上说,决定两种商品相互交换数量比例的是( )