1. 预备演员：understructure 基础 | understudy 预备演员 | undersurface 下面
2. 预备演员,替角：523. underdog: 受欺负者,弱者. | 524. understudy: 预备演员,替角. V. | 525. upstart: 突然升官的人,暴发户.
3. 练习做临时替角：understood,懂,获悉,理解,明白 | understudy,练习做临时替角 | undertaken,承担,从事,接受
4. 候补演员,替身：busybody爱管闲事的人,好事的人 | understudy候补演员,替身 | dowdy邋遢女人,懒散女人
1. 预备演员；替角儿
An actor''s or actress''s understudy is the person who has learned their part in a play and can act the part if the actor or actress is ill.
e.g. He was an understudy to Charlie Chaplin on a tour of the USA.
他是查理·卓别麟美国巡演期间的替角儿。
noun
1. an actor able to replace a regular performer when required
Synonym: standby
verb
1. be an understudy or alternate for a role
Synonym: alternate