a treaty between four powers的用法和样例：
- A treaty was concluded between three powers.
- Roosevelt’s idea of a treaty between industrialists and the authorities appeals to the Russian oligarch.
- A treaty between two countries to ensure that residents are not doubly taxed on the same source of income in more than one country.
- Central American Common Market. A trade organization started in 1960 by a treaty between Guatemala, Honduras, Nicaragua, El Salvador, and later Costa Rica.