I have some questions with English expressions

Hello, I'm ted.
Would you help me correct it?

1. He taught us the wrong expression to correct.
(Korean : 그는 우리의 잘못된 표현을 올바르게 고쳐준다(or 가르쳐준다))

2. It was him. It was he. (Which one is correct?)
It was him is correct
3. There are many group study. There are many of group study. (Which one is correct?)
There are many study groups
4. I choose to drink instead of smoking.
(Korean : 나는 담배 피는 대신에 술 마시는 것을 선택했다)
I choose to drink instead of smoke.
5. I haven't been smoking, I won't do that.
(Korean : 나는 담배 핀 적이 없으며, 앞으로도 그럴 것이다)

6. Drugs are prohibited in Korea legally.

Drugs are illegal in Korea

7. I'm like Peter Pan, I like to travel and to hang out.
(Korean : 나는 마치 피터팬 같다, 여행 하기 좋아하고, 놀러다니기 좋아하고)

Final,8. My parents were willing to allow me to quit school.
(Korean : 부모님은 내가 학교를 그만두는 것을 흔쾌히 허락하셨다)

Thank you for your reading my notebook!

You are absolutley welcome, I hope I was helpful