substitution

教练在比赛中进行了一次换人。

The coach made a ___substitution in the game.

用新巴士逐步替代旧巴士成本很高。

The gradual ___substitution of old buses with new ones is costly.

经理在比赛末段的换人改变了比赛的走向。

The manager's late ___substitution changed the course of the game.