“当副手”常见的英文表达有：
serve as a deputy
例句：He has been serving as a deputy in the team for several years.（他在团队里当副手已经好几年了。）
act as a deputy
例句：She will act as a deputy during the manager's absence.（经理不在时，她将当副手。）
be a deputy
例句：He was chosen to be a deputy in the project.（他被选为这个项目的副手 。）