单词：substitutions
n. 代替；代用；替换（substitution的复数）
n an event in which one thing is substituted for another
n the act of putting one thing or person in the place of another: "he sent Smith in for Jones but the substitution came too late to help
n the act of putting one thing or person in the place of another: "he sent Smith in for Jones but the substitution came too late to help
substitutions的用法和样例：
例句
用作名词(n.)
- Such substitutions dramatically affected the performance of U.S. agriculture in the past century.这种代替措施在过去一个世纪里显著影响了美国农业的效能。