时间状语从句.
如：
Each time I see her，as is often the case，she is always wearing a smile
each time 有的，表示每一次……的时候(相当于when)Each time I see you，I will remember the happy time we spent together.每一次我见你，就会想起我们一起度过的快乐时光.
Each time，意思是每当做某事的时候，引导的时间状语从句，例如，I bought a cup of tea each time I went out
