a contingent fund的用法和样例：
- Your hosting district may require a contingency fund for emergency situations.
- The BMO also provides that an OC may establish and maintain a contingency fund to provide for any expenditure of an unexpected or urgent nature.
- In addition, we could look into the need to provide guidelines for owners on building up a contingency fund to meet non-recurrent expenditure.
- A contingent of 400 Thebans remained.
- A contingent of soldiers was marching towards us.