covering them with all the clothes she could find
问题描述：
covering them with all the clothes she could find
这里的cover为什么要加ing形式呢?
答
前边的呢?句子不完整啊she turned a suitcase into a bed and put the children inside it, covering them with all the clothes she could find."she turned a suitcase into a bed and put the children inside it"中，已经有了句子主谓成分，所以不能再有其他主语，而cover这个动作的发出者也是she，这里是用动名词引导的“covering them with all the clothes”来作伴随状语了。如果后面动作的发出者不是she，而是另一个人的话，比如Tom，那么会变成“she turned a suitcase into a bed and put the children inside it, Tom covering them with all the clothes she/he could find.”这样就是独立主格结构了（当然，这个变出来的句子不太合逻辑，不过独立主格就是这样的，顺便记一下吧）如果第二句改成了Tom的话cover还是用加ing的形式吗？那Tom前面不需要加be？