选B. 首先你要知道seat 的用法 seat oneself on 或者be seated on 如果说他现在正坐在沙发上,应该是 he is seated on the sofa. 或者he seats himself on the sofa 因为seat和 dress一样都是及物动词,也就是在句子里面要么加宾语反身代词,要么用于被动语态.而sit是个不及物动词,所以虽然意思都是"坐"...
选B. 这里说明一点,be seated人做主语,意思是“就座,坐好了”是一种状态,而不是被动!!!!!!! 假如sit,就用sitting. There was a man seated beside it.有一个人坐在它旁边。 There was a man sitting beside it.有一个人正坐在它旁边。