feed...on和feedon的用法区别?既然是用某物为某人和以什么为食，那为啥用法一样?Thechildwasfeedingthemonkeyon/withabananaCattlefeedmostlyongrass.牛以草为主食

　　feed...on和feedon的用法区别?

　　既然是用某物为某人和以什么为食，那为啥用法一样?Thechildwasfeedingthemonkeyon/withabananaCattlefeedmostlyongrass.牛以草为主食