A: “I regret ____ so much trouble.” - B: “Well. Let’s forget all about that.”16/64Mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the following questions A: “I regret ____ so much trouble.” - B: “Well. Let’s forget all about that.”to have causedcausedto causehaving causedGiải thíchĐáp án : D Cấu trúc “regret + doing something”: hối hận, hối tiếc làm gì