learn,cost,let ,may mean .它们的过去式是什么

问题描述:

learn,cost,let ,may mean .它们的过去式是什么
learn,cost,let ,may mean ,meet,sell,smell,speak,spend ,teach,think它们的过去式是什么

learn---learned/learntcost----costlet---let ,may----mightmean----meantmeet----metsell----soldsmell----smeltspeak-----spokespend----spentteach----taughtthink----thought