as several of什么意思

as several of后面应该接了名词，即
as several of sth ....
这里as several of 并不是什么固定搭配，as只是连接词，这里应该表示原因的，即“因为一些。。。”
短语还是several of sth 一些...

例：Not all the vegetables are fresh,as several of them have gone bad.
不是所有的蔬菜都是新鲜的，因为有些已经变质了。