Bị động với modal và câu đặc biệt: Lý Thuyết

modal + be + V3 — sau modal (can, must, should, may...) luôn là be nguyên thể rồi V3.

• This problem can be solved easily.
• The homework must be done before Monday.
• Waste should be recycled.

Bẫy: ❌ can is solved → sau modal phải là be, không chia.

• have to → have to be + V3: The report has to be submitted today.
• be going to → be going to be + V3: A new bridge is going to be built here.

Động từ có hai tân ngữ (give, send, tell, offer...) tạo được hai câu bị động; đề thường lấy người làm chủ ngữ:

They gave her a prize. → She was given a prize. / A prize was given to her.

• I was sent an email. / We were told the news.

Với say, think, believe, report... có hai mẫu bị động:

• It is said that + mệnh đề: It is said that he is very rich.
• S + is said + to V: He is said to be very rich.

Nếu việc xảy ra trước thì dùng to have + V3: He is said to have left the country.

1. Sau modal luôn be + V3: can be done, must be finished — không chia be.

2. Đủ be: ❌ should recycled → ✅ should be recycled.

3. Bị động hai tân ngữ lấy người làm chủ ngữ: She was given... (không phải She was gave).

4. It is said that + mệnh đề khác S + be said + to V — chọn đúng mẫu theo cấu trúc còn lại trong câu.