have worked in this school since 2000请问这句和have been working here since 2001意思是不是一样的?

I have worked in this school for three years.同义句改写 I have worked in this university _______ 1980.A for B since C till The Blacks ___ in this factory since 1998 A has worked B has come C have been Dhave arrived I could hardly see anything () the dense fog.(since for)They have worked in this company () they graduated.(since for) have worked in this school since 2000请问这句和have been working here since 2001意思是不是一样的? 问道英语改错题谢谢解答..I have been told one more worked in this year 为什么要把in去掉? He;s worked in this factory for many years In this circle have Did you have difficulty in study?Yes,____ out the math problem like this.A.work B.worked...Did you have difficulty in study?Yes,____ out the math problem like this.A.work B.workedC.working D.to work 第一句：David worked in this city years ago【改为同义句】第二句：They have lived there since〔 1995〕对扩号内提问 have you ever worked in a company与have you worked in a company有什么区别, ________harder,you would have passed this exam.A.If you have worked B.If you worked C.Were you to work D.Had you worked I have worked in this city for about 30 years.同义句I have worked in this city ____ ____ ____ ____ ____.还有也改同义句：You must look after yourself well .You must _____ _____ ____ _____ yourself. ___harder,you could have have passed this exam.(B)A.Were you worked B.Had you worked C.if you worked D.If you have worked请详解一下,同时翻译一下 -Have you __ worked in a company -Of couse.I worked in a radio company __ four years. _____ hard before, Tom is afraid of failing in the exam. A. Having been worked B. Not to have worked C. Having never worked D. Never have worked为什么选C而不可以用Never having worked My mother has worked in this factory 2 years.My mother has worked in this factory _____ 2 years.(A)about (B)for (C)in (D)since Mary ___on her new priject late last night ,so she felt sleeply in the office this morninga.must work b.must have been working c.must be working d.must have been worked选什么.