He has been working in the factory___.A.ever since B.10 years ago C.since 10 yearsD.10 years before求详解,最好每个选项都讲解一下!

问题描述:

He has been working in the factory___.A.ever since B.10 years ago C.since 10 years
D.10 years before
求详解,最好每个选项都讲解一下!