1.seat和sit作为动词,都可以表示“坐”的意思.
(1) seat是及物动词,比较正式,常以被动形式表示主动意义.如：
He is seated between Jack and Tom.　她坐在杰克和汤姆之间.
Please be seated.(=Please seat yourself.) 请坐.
(2) sit通常作不及物动词用,比较口语化.如：
The students are sitting at their desks.　学生们正坐在课桌旁.
Sit down,please.请坐.
2.seat还可作名词用(而sit只能作动词用),常见短语take a seat (相当于have a seat或take one's seat) ,意为“坐下,就座”.如：
Take your seat,please.请就坐.