solidworks生成同步带:请教~~can和 could 的区别

请教~~can和 could 的区别 can,could,may,might之间的区别？ 请问can和could、may和might有什么区别 老外在说can和can't的时候我听不出来区别，请教！ would和could之间的区别？ could you和would you的区别 could you tell me 与can you tell me 的区别是什么 can't have done与could't have done的区别 情态动词can(could)的用法 could和should表示提建议时的区别