a herd of livestock的用法和样例：
- We saw a herd of elephants yesterday.
- The herdsman looks after a herd of animals.
- The children come galumph into the house like a herd of elephant.
- The photographer took a photo of a herd of elephants.
- The children came galumphing into the house like a herd of elephants.
- The milkman selected the spotted cows, from among a herd of two hundred.