it is 3 weeks since he worked here 啥意思,请专业些的人解答

it is 3 weeks since he worked here 啥意思,请专业些的人解答 It is ten years since my aunt worked here.为什么整句话表示的是aunt已不在这 It has been three weeks since he lived here with us and now_ 求It is three years since he worked in his office.解释下since 改错：It is 3 weeks since Ihave seen him. it is ten years since he worked here为什么既指他已经在这工作十年了,又指他不在这工作 It is about half an hour since he came here. he has been here since five weeks ago. it is three years since he moved here 的同义句转换! 分析一下它的含义?It is has been four years since he lived here． Is it two weeks since he left London 可以这样改吗 It's two years since I worked here