1、科普版六年级英语下册课件Lesson2It’s on the fifth floorone1stfirsttwo2ndsecond3rdthirdthreefour4thfourth序数词的变化1one-----first2two------second3three----third4其余的序数词都是由基数词后加-th变化而来的吗?six6thsixthseven7thseventheight8theighthfive5thfifthnine9thninthtwelve12thtwelfthel