IV. Nối câu dung Which (2ps):
1. She study very hard. This makes her parents feel happy.
She studies very hard, which makes her parents feel happy. 
2. Peter often stays up late.This makes him feel tired.
-> Peter often stays up late, which makes him feel tired
3. He couldn't come to the party.This was a pity.
-> He couldn't come to the party, which was a pity 
4. She is lazy.This makes it difficult for her to pass the exam.
-> She is lazy, which makes it difficult for her to pass the exam