- second in command (to somebody)
a person who has the second highest rank in a group and takes charge when the leader is not there 副指挥官；二号人物 For twenty years he served the business as second in command to his father. 二十年来，他一直是他父亲的第二把手。 his second in command, Major Thursby 他的第二指挥官瑟斯比少校 She is second in command. 她是二把手。