must,can,may ,should,would,need和shall的区别

1. can (could) 1）表示能力,could主要指过去时间. Two eyes can see more than one. 两只眼比一只眼看得清. Could the girl read before she went to school? 这女孩上学前能识字吗? 2）表示可能（理论上或是逻辑判...