their和theirs有什么区别

theirs 和their's 有什么区别? their和theirs有什么区别 their和theirs的区别 英语their和theirs的区别 some pictures of them和some pictures of theirs有什么区别 their和theirs的用法是什么? their 和 theirs 的用法各是什么? his him her she it its they their theirs our ours us we 各有什么 their和them的用法有什么区别 their's与theirs 英语our是什么格?宾格?主格?人称代词?还是什么?内个，they，their，theirs，哪个和our同类？ 做“低头”说,low their heads和lower their heads有什么区别?