engagement letter的用法和樣例：
例句
- A ceremony was held in Beijing, during which the AMSS Director, Professor Guo Lei, presented the appointment letter to Professor Tang.
聘書頒發儀式在北京舉行，由郭雷院長親自頒發。 - The letter of attorney must list the items of trust and the limit of powers.
授權委託書必須記明委託事項和許可權。 - By Letter of Proxy, one agent may represent more than one directors.
根據委託書，一名代表可以代表一名以上的董事。
