sheep前面可以加a嗎

前面可以加a，例如：

1、There is a sheep under the tree.樹下有一隻綿羊。

2、A goat is different from a sheep.山羊與綿羊不一樣。

3、The path was no better than a sheep track.那條小路簡直就像是羊腸小道。

4、I'd kinda like to have a sheep farm in New Mexico.我有點兒想在新墨西哥州開一個牧羊場。