Giúp mình với!

I'd be happy to help you with these exercises. Here are the answers with explanations in Vietnamese: **C** 1. They were having tea when the doorbell rang. (They đang uống trà khi chuông cửa đổ chuông.) 2. Father was smoking his pipe while mother was reading a magazine. (Bố đang hút ống điếu trong khi mẹ đang đọc tạp chí.) 3. While he was mowing the lawn, it started to rain. (Khi anh ấy đang cắt cỏ, trời bắt đầu mưa.) 4. He was having breakfast when the toaster blew up. (Anh ấy đang ăn sáng khi lò nướng bánh mì phát nổ.) 5. When I came into the office, my boss was waiting for me. (Khi tôi vào văn phòng, sếp của tôi đang chờ tôi.) 6. When we saw Brian, he was driving a taxi. (Khi chúng tôi thấy Brian, anh ấy đang lái taxi.) 7. Father was waiting in the car while mother was doing the shopping. (Bố đang chờ trong xe trong khi mẹ đang mua sắm.) 8. When he arrived, we had dinner. (Khi anh ấy đến, chúng tôi đã ăn tối.) 9. While they were playing chess, we went shopping. (Khi họ đang chơi cờ, chúng tôi đi mua sắm.) 10. They were having a party while he was sleeping. (Họ đang tổ chức tiệc trong khi anh ấy đang ngủ.) 11. He took a photo when I was feeding the ducks. (Anh ấy chụp ảnh khi tôi đang cho vịt ăn.) 12. They were playing football when the lights in the stadium went out. (Họ đang chơi bóng đá khi đèn trong sân vận động tắt.) 13. While George and John were cleaning their room, she was doing the ironing. (Khi George và John đang dọn phòng, cô ấy đang ủi quần áo.) 14. Sam was doing the ironing when Jack phoned her. (Sam đang ủi quần áo khi Jack gọi điện cho cô ấy.) 15. We were waiting at Victoria station when the train arrived. (Chúng tôi đang chờ tại ga Victoria khi tàu đến.) **D** 1. They were playing cards when the postman came. (Họ đang chơi bài khi nhân viên bưu điện đến.) 2. I was sweeping the floor when I heard a noise. (Tôi đang quét sàn khi tôi nghe thấy tiếng động.) 3. She was watching TV when the doorbell rang. (Cô ấy đang xem TV khi chuông cửa đổ chuông.) 4. We heard a cry and ran into the kitchen. (Chúng tôi nghe thấy tiếng kêu và chạy vào bếp.) Let me know if you have any questions or need further clarification!