★seat n.座位 vt.让某人就座
have a good seat/place，这里的seat指place(指地点)，而不是chair.
take a seat/take your seat 坐下来, 就坐
Is the seat taken? 这个位置有人吗?
请坐的3种说法 :
Sit down, please. (命令性)
Take your seat, please.
Be seated, please. (更礼貌)
作为动词的seat与sit的区别
sit（sat，sitten） vi. 就座
He is sitting there. 他坐在那儿。
seat vt.让某人就座
seat sb. 让某人就坐，后面会加人
(选择题) When all those present(到场者)_ D_ he began his lecture.
A. sit B. set C. seated D. were seated
