Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questions.
It was not until the students were seated ______ the proctor realized he had the wrong test booklets.
A. as soon as
B. that
C. and
D. when
Đáp án B
Cấu trúc: It….not until….that: Mãi cho đến khi
Tạm dịch: Mãi cho đến khi sinh viên được xếp chỗ xong thì giám thị mới nhận ra ông ấy có nhầm sách kiểm tra