. People should send their complaints to the head office. A.Complaints should be send to the head office by people. B.Complaints should be sent to the head office. C.Their complaints should send to the head office by people. D.Their complaints to the head office should be sent.

Cách làm:
- Nhận biết đây là câu hỏi yêu cầu chuyển từ câu đề sang dạng bị động.
- Tìm chủ ngữ và vị ngữ trong câu đề.
- Sắp xếp lại cấu trúc câu theo dạng bị động.

Câu trả lời:
B. Complaints should be sent to the head office.

Their complaints to the head office should be sent.

Their complaints should be sent to the head office by people.

Complaints should be sent to the head office.

Complaints should be sent to the head office by people.