大家好,我在文法书上面看到一段文章,有点小小的疑问想请教,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.
以上文章的文法时空背景应该是设定在过去的时间,但是为什么look会是ing的形式呢?
恳请神人不吝赐教,谢谢