a pair of oxen的用法和样例：
- A pair of oxen, yoked together, was used.
- I bought a pair of tan leather shoes the other day.
- A crossbar with two U-shaped pieces that encircle the necks of a pair of oxen or other draft animals working together.
- Billy has a pair of new trousers.
- This small animal has a pair of hazel eyes.
- He was dressed in a pair of black trousers.