分类：教育/科学-外语学习-英语考试
问题：doyouwishtoflyfirstclass,busines? 
do you wish to fly first class, iness or economy？ 为什么fly后面不用加by我觉得应该是do you wish to fly by first class, business or economy？
回答：Usually, you would use "by" when you convey the meaning "on."  traveled by plane to their destination.Do you want to travel by bus or by cab?Using your sentence, "do you wish to fly first class, business, or economy?" The sentence already indicates that the person is flying by plane, so "by" isn't necessary.Hope this helps.