Since I have seen you

Since I have seen you have .since did区别have .since have done?eg：I haven’t seen you since I’ve been back.I haven’t seen you since I was back. I have not seen her since 1997保持原句意思 I saw her was in1977 辨别英语句子 1 i have never seen him since he was ill 2 i have never seen him since fell ill.辨别英语句子 1 i have never seen him since he was ill 2 i have never seen him since fell ill. how long has it been since I have seen one!是感叹句吗 i have seen it Oh,I have seen I have seen him before have后面应该用什么词 just already never ever 还是since I have been here since I was born 和I haden't seen him since he left NANJING.两句话为什么用的不是相同的时态? this is the first film i have seen since i came here.中间填that还是which,为什么 I have not seen her since 1997保持原句意思I saw her was in 1977 I met my brother yesterday ,whom I ( )him since he left homeA.have not seen B.had not seen C.did not see D.do not see Seldom__my boss in such good mood since I came to work in this companyA I saw B I have been C have I seen D do I see it is three years since i have seen himit is three years since i saw him有什么不同.表达效果还是意思什么的? It is two weeks since I have seen him.( have seen-- saw)谁能够帮我讲出一个所以然?麻烦题目看清啊——就是把HAVE SEEN改成了SAW 这是为什么？什么理由？ T‘have seen what I have seen,see what I 改错句:It is two weeks since I have seen him要说出具体原因,确切点 Deceived all i have seen