IX:
Mark the letter A, B, C or D on your answer sheet to indicate the underlined part that needs correction in each of the following questions.
Trả lời câu hỏi dưới đây:
It was suggested that Tom studied the document more thoroughly before attempting to pass the exam.
Đáp án là B. studied => had studied, vì QKHT + before + QKĐG/ V-ing