=>
1. He said : "I will not/won't have enough time to finish the job." 
-> câu tường thuật lùi từ will -> would (chuyển về dạng trực tiếp dùng will)
2. When was that chocolate cake eaten by your friends?
-> bị động QKĐ was/were V3/ed
3. My teacher asked what the skills I concerned most were.
-> tường thuật dạng WH questions : asked sb + từ để hỏi + S + V (lùi thì, HTĐ -> QKĐ)
4. The Little Prince is the most interesting novel (that) I have ever read.
-> so sánh nhất the most adj/ thì HTHT have/has ever V3/ed
5. If you don't finish your homework, you can't go out with your friend.
-> or : nếu không/ câu đk loại 1 If S Vs/es, S can (can't) V.
6. They're not sure how to operate the new system.
-> how to V : làm thế nào để