some grass to sheep
sheep 单复数都有一样题目问的是这个：People often feed some grass ()sheep. 填介词介词 to 人们经常把一些草拿去喂羊。那feed on 和feed with 又分别是什么意思呢？feed with拿某东西喂feed on 以某东西为食feed the sheep with some grass用草喂羊sheep feed on grass羊以草为食