People may travel by flying cars or hot air balloons. (27) _________, at the present, a company is designing an electronic train.Đoạn văn27/40People may travel by flying cars or hot air balloons. (27) _________, at the present, a company is designing an electronic train.However Therefore Otherwise ThoughGiải thíchHướng dẫn giải: Đáp án đúng: A However: tuy nhiên