大家好,我在文法書上面看到一段文章,有點小小的疑問想請教,文章如下 Stella was alone in a strange city.She walked down the avenue slowly,looking i n shop windows.Suddenly,she turned her head and looked behind her.Someone had called her name. 以上文章的文法時空背景應該是設定在過去的時間,但是為什麼look會是ing的形式呢? 懇請神人不吝賜教,謝謝