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？

The National Day is coming.It is__A two week's away . B in two weeks' timeC in two weeks' away D. two weeks far Is it two weeks since he left London 可以这样改吗He has been to London for two weeks the computer is very expensive.I bought it two weeks ago.the computer is very expensive.I bought it two weeks ago 合为一句! It is two weeks ----- christmas and Mrs Smith is very busy填空 It is two weeks since we met last time 是什么从句? it is nice day in shanghai .对nice提问.i will stay in london for two weeks .对for two weeks 提问 two weeks When have you bought the book?Two weeks ago.I have bought it for two weeks. The problem so very complicated that it took us nearly two weeks to solve it.The problem so very complicated that it took us nearly two weeks to solve it.The problem is so very complicated that it took us nearly two weeks to solve it.哪句有问题, 改错句:It is two weeks since I have seen him要说出具体原因,确切点 she is staying in Shanghai for two weeks 对for two weeks 提问 -Is this your room?-No,it's___room.A.the children B the children's C.two week time D.two weeks time It took my daughter two weeks ______the novel____by yanghongying I visited a farm two weeks a( ).It was fun 英语翻译下一句是was it two weeks of complete enjoyment? _____a big party in our school in two weeks A it is B it willbe C there was D there is going to be It is two to two. 她可以休假两个星期 英文翻译she is()()()two weeks ()