He has been working here.为什么要用working?

He has been working here.为什么要用working? he()in the laboratory the whole morning.A.has been working ,B.is working,c.has worked John has been working on the essay whole afternoon and he still( Ahas been B does C has DisJohn has been working on the essay whole afternoon and he still( Ahas been B does C has Dis He has been working there for three years是啥意思?好的我天天顶 He has been working the whole moring and he still___ A.does B.is C.has D.has been为什么选B不选A? has been worked和has been working的区别 He is one of the foreign experts who___in China.A.works B.is working C.are working D.has been working She has been working for 20 hours has been working on his degree是什么意思 he has been working on his book for the past two mouths when at last he got home翻译 has been working 和was working有什么区别 he has been working there ( ) 1998.he has been working there ( ) 1998.1 after 2 in 3 since 4 until是3还是4 我不是很清楚 告诉我下为什么这样选 Jim ____ here since he came here.A.has been working B.works C.had worked D.worked he ( )there for a few months and then went to America,填worked 还是has been working Tom was tired.He _______ all day.A was working B.has worked C worked ,Dhad been working分析一下原因 If he ——,don’tinterrupt him.A.still works B.is still workingC.still has been working D.will still be working He____on his new book for months before he fell ill,or we would have found it in the market.A.had been working B.has been working C.was working D.will have worked By next year he ---in New York for five years.A has worked B has been working C works D will have worked