He ______ English for three years before he went to Canada last yeara、had studiedb、had been studyingc、studiedd、has studied

分类: 作业答案 • 2022-01-02 14:00:37

问题描述：

He ______ English for three years before he went to Canada last year
a、had studied
b、had been studying
c、studied
d、has studied

答