“当保姆”常见的英文表达有 “work as a babysitter” 或 “serve as a babysitter” 。
work as a babysitter：强调从事保姆这份工作这一行为。例如：She decided to work as a babysitter during her summer vacation.（她决定在暑假期间当保姆。）
serve as a babysitter：更侧重于说明扮演保姆这个角色。例如：I often serve as a babysitter for my neighbor's kids.（我经常给我邻居的孩子当保姆。 ）