a congratulatory letter的用法和样例：
- British Deputy Prime Minster John Prescott sent a congratulatory letter to the company.
- State Council Premier Peng Li, who is on an overseas visit, sent a congratulatory letter to the meeting.
- He didn't know he was enrolled until he received a congratulatory letter from the school.
- George Weber, secretary general of the International United Association of the Red Cross Society and the Red Crescent Society sent a congratulatory letter to today's meeting.
- President Jifei Wan from China Council for the Promotion of International Trade, Chamber of International Commerce China sent a congratulatory letter to the general assembly.