be seen 的用法

seen的用法 单词smoke的用法”The smoke from the forest fire could be seen ten have been seeing /have been seen/ have seen的用法. sb be seen doing 有这种用法吗? 请教see、seen、saw、seeing的用法? once to be seen 和once being seen的区别 can be seen 和 can been seen 的区别? see sb do/doing ; be seen to do/doing 和这里see用法类似的词有哪些? seen in 用法 having seen是什么用法 be sure的用法 be born的用法