1N-VOC (对不知其姓名的男士或上级的尊称)先生,长官 People sometimes say sir as a very formal and polite way of addressing a man whose name they do not know or a man of superior rank. For example, a shop assistant might address a male customer as sir . (对不知其姓名的男士或上级的尊称)先生,长官 [politeness]
Excuse me sir, but would you mind telling me what sort of car that is?.
先生,请您告诉我那是什么类型的车好吗?
Good afternoon to you, sir.
下午好,先生。
2N-TITLE (用于爵士或准男爵的姓名前)爵士Sir is the title used in front of the name of a knight or baronet. (用于爵士或准男爵的姓名前)爵士
She introduced me to Sir Tobias and Lady Clarke.
她把我引见给了托拜厄斯爵士和克拉克夫人。
3CONVENTION (正式信函或商务信函开头的称呼语)先生,阁下(写信给某组织时使用 Dear sirs) You use the expression Dear sir at the beginning of a formal letter or a business letter when you are writing to a man. You use Dear sirs when you are writing to an organization. (正式信函或商务信函开头的称呼语)先生,阁下(写信给某组织时使用 Dear sirs)
Dear Sir, Your letter of the 9th October has been referred to us.