a brief letter的用法和样例：
- Keefer also sent a brief letter to Dennis questioning his allocation formula.
- They were accompanied by a brief letter to the effect that the syndicate was overstocked, and that some months would elapse before it would be in the market again for manuscripts.
- After a brief rally share fall back to a new low.
- He gave us a brief introduction about his company.
- They married after a brief courtship.
- A brief, indefinite interval of time.