I have been doing sth.和I have done sth.有何区别?麻烦各位帮我解决一下英语问题,谢谢!

i has been doing 还是i have been doing have been doing sth Celia asks,What have you been doing these days?Celia asks () I () been doing those days. have been doing 神马意思? what you have been doing Maybe I'm not perfect,but I have been doing myseMaybe I'm not perfect,but I have been doing myself.语法对吗 has been doing have been done区别 have been doing ,have done和have doing区别 I have been dreaming to be a teacher all the time.all the time 和have been doing是否重复? i have been to和i have been doing 和i have been.区别i have been to和i have been doing 和i have been+done内些的区别~解释清楚点,内些死定义不太明白譬如说 我已经读过这本书我曾经买过一辆车都怎么说， have been doing 为什么还有 have been deadj have been do和have been doing的不同 翻译I have been doing my research work in this institute since last year. 英语：现在完成时应该什么时候使用?还有I have been doing这种形式又应该何时使用? What have you been doing s__ I saw you last time? I’ll go to the library as soon as I finish what IA.was doing B.am doing C.have done D.had been doing have been doing,had been doing,will have been down是什么 英语比较厉害的 关于 have been 的用法的~have been do sth.have been doing sth.有什么区别?比如：I skated for 4 hours.和 I have been skated for 4 hours.有什么区别?