However hard Tim tried to win the contest, he didn't succeed.

47/50

No matter how hard Tim tried to win the contest, he didn't succeed.

Tim tried to win the contest and succeeded.

Although Tim tried hard to win the contest but he didn't succeed.

It was hard for Tim to win the contest because he never succeeded.

Giải thích

Đáp án A

"Dù Tim đã cố gắng hết sức để thắng cuộc thi nhưng cậu ấy không thành công."

B, D: sai nghĩa; C: sai ngữ pháp (bỏ "but")

However + adj/ adv + S + V ~ No matter how + adj/ adv/ S + V (dù thế nào đi nữa...)