1/13 working hard or hardly working?

Today, teacher taught us how to use adverb. He said "some adverb put on different position. There are different meaning." For example. working hard means " work a lot", hardly working means " work very little". I had a thought immediately.

Last week, someone told me "He decided to study very hard", but in the moning, I saw him to asked his classmate to copy her homework. Maybe now, he hardly studied.