Mark the letter A, B, C, or D on your answer sheet to indicate the cor

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questions.    

The wall _______________________ before you paint it.

• A. A. must be cleaned
• B. B. should cleaned
• C. C. might been cleaned
• D. D. No answer is right

Dịch: Bức tường này phải được lau sạch trước khi bạn vẽ lên nó.
Dựa vao nghĩa chọn A