I saw a UFO-over my head when I was walking toward the bus stop yesterday.中间填是fly flew 还flying
问题描述：
I saw a UFO-over my head when I was walking toward the bus stop yesterday.中间填是fly flew 还flying
答
Flying.理由：“see”在该句中是使役动词,有两种固定搭配：1.see sb/sth do（看见...做完了...）2.see sb/sth doing（看见...正在做...）,因此排除flew.“when i was walking towards the shop”是一个瞬间的动作,表...