=>
I/
1. The man asked me if my father was working for that company then. ( câu tường thuật, this -> that/now -> then)
2. If you don't work hard, your parents will be unhappy. ( câu đk loại 1 If S Vs/es, S will V )
3. A new stadium was being built when we came. ( bị động QKTD : was/were being V3/ed)
4. He started reading the book two days ago. ( chuyển thành QKĐ : S started/began Ving...+ time)
5. She wishes she were the most beautiful girl in the world. ( câu ước -> lùi thì)

II/
1. The teacher said that the students had to follow the school plan. ( câu tường thuật have to -> had to )
2. We decided to go for a short walk before sitting down for lunch. ( decide to V : quyết định làm gì)
3. Although he didn't like listening to music, he went to the concert with her last week. ( Although S V : mặc dù)

1. Unless the weather is nice, we will stay at home. ( Unless = If...not)

2. Neil Armstrong, who walked on the moon, lived in the USA.