新概念二册 的52课：This has not been easy

新概念二册 的52课：This has not been easy 我想请问你一下新概念二52课中 This has not been easy because i own over a this has not been easy.中has not been什么意思?怎么来的?具体点 this has not been easy与this is not easy区别 This has not been easy 和 this is not easy 不是一个意思吗 新概念英语二77课,happen用了完成时,为什么?this is has not happened. 新概念二册52课将答案用括号的词连起.Why has this proved difficult?Do they cov This has not been easy because i own over a thousand books.这 This has not been easy because I own over a thousand books. 英语翻译this has not been easy because i own over a thousand boo she has not been around this week 新概念二册.1.He has been ringing up continually ____ lunchtime.2.