英语语法分析

The sheepdog rounded up all the sheep.

牧羊犬把所有的羊赶拢在一起。

When does a sheepdog become a sheepdog?

牧羊犬何时才能成为真正的牧羊犬？

She had brought her trained sheepdog to help in the rescue.

她带来了经过训练的牧羊犬帮助营救。