"Where did you take a vacation last summer?" A. He asked Lan where she had taken vacation last summer. B. He asked Lan where she had taken vacation the summer before C. He asked Lan where had she taken vacation the summer before Giải thích luôn nha.

B. He asked Lan where she had taken vacation the summer before

Giải thích:

S + asked/ wondered/ wanted+ WH + S +V…

- Lùi thì của động từ: take -> taken ( QKĐ -> QKHT)

- Đổi đại từ nhân xưng: you -> she

- Đổi cụm từ chỉ thời gian : last summer -> the summer before