摘要:
3.1 基本概念
3.2 关系的合成
3.3 关系上的闭包运算
3.4 次序关系
3.5 等价关系和划分 阅读全文
摘要:
a bottle / some water (countable/uncountable 1); a cake / some cake some cakes (countable / uncountable 2);a/ an and the 比较;THE用法;go to work / go home/ go to the cinema;l like music / I hate exams;the....(地名) 阅读全文