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.    

___, she had studied English.

• A. A. Before she came to London
• B. B. By the time she comes to London
• C. C. While she was in London
• D. D. After she came to London

Vế sau chia ở quá khứ hoàn thành -> Vế trước xảy ra trước, ở quá khứ đơn
=> A
Tạm dịch: Trước khi tới London, cô ấy đã học tiếng Anh;