I'd be happy to help you with these exercises. Here are the answers with explanations in Vietnamese:
8. Jimmy didn't answer the phone because he was studying.
→ If Jimmy hadn't been studying, he would have answered the phone.
(Dịch: Nếu Jimmy không đang học, anh ấy sẽ trả lời điện thoại.)
9. John is exhausted today because he didn't sleep well last night.
→ If John had slept well last night, he wouldn't be exhausted today.
(Dịch: Nếu John đã ngủ ngon đêm qua, anh ấy sẽ không mệt mỏi hôm nay.)
10. Sarah can't park near her office, that's why she doesn't come by car.
→ If Sarah could park near her office, she would come by car.
(Dịch: Nếu Sarah có thể đậu xe gần văn phòng của cô ấy, cô ấy sẽ đến bằng xe.)
11. I don't know Lana's email address, so I can't send her the document.
→ If I knew Lana's email address, I would send her the document.
(Dịch: Nếu tôi biết địa chỉ email của Lana, tôi sẽ gửi tài liệu cho cô ấy.)
12. Karen is not tall enough to join the basketball team.
→ If Karen were tall enough, she would join the basketball team.
(Dịch: Nếu Karen cao đủ, cô ấy sẽ tham gia đội bóng rổ.)
13. Ronald doesn't see the signal so he doesn't stop the car.
→ If he saw the signal, he would stop the car.
(Dịch: Nếu anh ấy thấy tín hiệu, anh ấy sẽ dừng xe.)
14. Peter gets bad marks today because he didn't prepare his lessons well.
→ If Peter had prepared his lessons well, he wouldn't get bad marks today.
(Dịch: Nếu Peter đã chuẩn bị bài học tốt, anh ấy sẽ không nhận được điểm kém hôm nay.)
15. Mary doesn't save enough money. She can't buy a new home.
→ If Mary saved enough money, she would buy a new home.
(Dịch: Nếu Mary tiết kiệm đủ tiền, cô ấy sẽ mua một ngôi nhà mới.)
16. Go right now or you'll be late for the bus.
→ If you don't go right now, you'll be late for the bus.
(Dịch: Nếu bạn không đi ngay bây giờ, bạn sẽ trễ xe buýt.)
17. Karik doesn't apply for the job because he doesn't have an IELTS certificate.
→ If Karik had an IELTS certificate, he would apply for the job.
(Dịch: Nếu Karik có chứng chỉ IELTS, anh ấy sẽ nộp đơn xin việc.)
18. Hurry up, or we will be late for work.
→ If we don't hurry up, we will be late for work.
(Dịch: Nếu chúng ta không vội vàng, chúng ta sẽ trễ giờ làm việc.)
19. They don't understand you because you don't want to talk to them.
→ If you wanted to talk to them, they would understand you.
(Dịch: Nếu bạn muốn nói chuyện với họ, họ sẽ hiểu bạn.)
20. Without your help, I couldn't find her address so quickly.
→ If I hadn't had your help, I couldn't find her address so quickly.
(Dịch: Nếu tôi không có sự giúp đỡ của bạn, tôi sẽ không thể tìm thấy địa chỉ của cô ấy nhanh chóng như vậy.)
21. Shut up, otherwise, you can't follow what the teacher is saying.
→ If you don't shut up, you can't follow what the teacher is saying.
(Dịch: Nếu bạn không im lặng, bạn sẽ không thể theo dõi những gì giáo viên đang nói.)
22. But for the heavy rain, we would have a good picnic on Sunday.
→ If it hadn't been for the heavy rain, we would have had a good picnic on Sunday.
(Dịch: Nếu không có mưa nặng, chúng ta sẽ có một picnic tốt vào Chủ nhật.)
23. Unless Nam apologizes to me, I won't talk to him again.
→ If Nam doesn't apologize to me, I won't talk to him again.
(Dịch: Nếu Nam không xin lỗi tôi, tôi sẽ không nói chuyện với anh ấy lại.)
24. Melly was sick, so she couldn't take part in the contest.
→ If Melly hadn't been sick, she would have taken part in the contest.
(Dịch: Nếu Melly không bị bệnh, cô ấy sẽ tham gia cuộc thi.)
25. Lam doesn't like spicy food, that's why he doesn't eat any food at the party.
→ If Lam liked spicy food, he would eat some food at the party.
(Dịch: Nếu Lam thích đồ ăn cay, anh ấy sẽ ăn một số đồ ăn tại tiệc.)