wangqh2696122 The teacher helped/ had helped him , otherwise they would never have been able to solve the problem. wangqh2696122, You should pay attention to the use of pronouns. You have him / they mix up.
New words, one handy idiom, and a 2-minute quiz — delivered to your inbox to keep your streak alive.
wangqh2696122""He would never have been able to solve the problems had it not been for the teacher's help."?This is ok.
wangqh2696122 The teacher helped/ had helped him, otherwise they would never have been able to solve the problem.This is really two sentences, and it's fine with or without 'had'. I think I would use 'had'.