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.
It was not until she could read and write when she was allowed to use smartphone.
A. not until
B. when
C. allowed
D. use
Đáp án B.
Đổi when thành that
Cấu trúc: It was not until … that + S-V.