also under-study, 1852, in the theatrical sense "memorize a part so as to be capable of performing on short notice it in the absence of the one to which it is assigned," from under + study (v.). The noun is attested from 1848, translating Italian supplimento.
实用例句
1. The leading player is ill. Let his understudy to appear on the scene.
主角演员病了, 让他的替角出场.
来自《现代汉英综合大词典》
2. 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。
来自辞典例句
3. The understudy was substituted when the leading actor fell ill.
主角演员患病,由替角代替演出.
来自辞典例句
4. The understudy is substituted when the leading actor falls ill.
“主角演员患病,由替角代替演出”.
来自互联网
5. When the star became sick, his understudy stepped into his part.