How do you say "to stop doing something" In Korean?
For instance, what if I wanted to say, "I stopped running yesterday"? Would it be "어제는 달릴 중단했어요"?

Question

How do you say "to stop doing something"  In Korean?
For instance, what if I wanted to say, "I stopped running yesterday"? Would it be "어제는 달릴 중단했어요"?

Answer

저는 어제 달리기를 중단했어요.

If you want to say you quit something, Korean normally use '그만두다, 끝내다' .
So "I stopped running yesterday" can be "저는 어제 달리기를 그만두었어요."

And if you want to say just stopping of action and you will continue later, '멈추다, 중단하다' would be natural. 
"저는 어제 달리기를 중단했어요"

Answer

어제는 달리기를 중단했어요.