by We all believe that a happy marriage should be _______ mutual love.
A. based on
B. concerned with
C. confided in
D. obliged to
Xem đáp án
Đáp án: A
Giải thích: Be based on + N = dựa vào cái gì
To be concerned with: quan tâm tới
To be obliged to: có nghĩa vụ
