Question

The book has been translated into thirty language since it came on the market in 197

came 能不能改成had come 。理由？？

Answer 1

不可以
原因：一、若since引导的状语从句的谓语动词是非延续性动词的过去时，则从句表示的时间是“从动作开始的那一时刻起”。如：
He has studied very hard since he came to our school.自从他来到我们学校，他学习就非常努力
came是非延续性动词。不能用完成时态，因为非延续性动词不能表示延续性动作

Answer 2

指的是197时间点，只能用CAME，