fill-in
n. 临时填补空缺的人；代替者；补充物
近义词：substitute，stand-in，temp，replacement，temporaryworker，alternate，casualworker，locum，supplyteacher，acting，summary，second，relief，reliever，backup，
英英释义
Noun
- someone who takes the place of another (as when things get dangerous or difficult);
"the star had a stand-in for dangerous scenes" "we need extra employees for summer fill-ins"
例句
用作名词(n.)
- There won't be any difficulty in finding a replacement.找一个代替者不会有什么困难。