he has worked as a report since 2000,根据since 2000提问?

he has worked as a teacher for only two weeks .he has little e ____ he has worked as a teacher months ago改为he ( )to work as a teacher mongths ago John　has　worked　as　a　sales　manager　since　he　（join）____this　company　in　2002. he has worked as a report since 2000,根据since 2000提问? He works as a teacher now,but he ___ on a farm for 3 years.A.worked B.has worked C.had worked D.woHe works as a teacher now,but he ___ on a farm for 3 years.A.worked B.has worked C.had worked D.wokes答案给的是A,但是为什么不能选C过去完 He (s ) as a waiter in that restaurant .He has worked there for two years.填入s开头的单词 ____ that time he has worked as a translator.A since B by C before D at选什么 为什么 Mr.white works as a journalist at present,but he ___in a high school for several yearsA.has worked B.worked C,had worked D.has been working 请详细说明为什么 john has worked as a sales manager since he (join)_joined____this company in 2002答案是joined 为什么呢 He has worked as a reporter since 2000（划线提问）划线since 2000_____ ______ _____ he _____ as a reporter. He works as a teather now,but he__on a farm for three years .A.worked.B.has worked 请回答选A还是...He works as a teather now,but he__on a farm for three years .A.worked.B.has worked 请回答选A还是B并解释一下为什么 ___ then,my mom has worked as a teacher. After g( ),he worked as a clerk in a company He said he ( ) in that factroy since 1949.A.has worked B.had worked C.worked D.was working Jackson has worked in the bank＿＿he left school. A.when B.since C.as soon as D.whether He has worked for a whole day回得来 He worked as a doctor at first.是什么意思 She _____ as a nurse ____ a year A.works;since B.has worked;for C.has worked ;since D.worked;for要原因,详细