1)现在完成进行时态(have/hasbeen+-ing分词构成):动作或状态从过去某时开始,继续到现在,可能继续下去,也可能刚刚结束.
I’vebeenwritinglettersforanhour.
I’vebeensittinginthegarden.
2)过去完成进行时(由hadbeen+ing分词构成):过去某个时刻以前一直在进行的动作
I’dbeenworkingforsometimewhenhecalled.
Wehadbeenwaitingforherfortwohoursbythetimeshecame.
3)将来完成进行时:将来某个时刻以前一直在进行的动作.
Bynextsummer,hewillhavebeenworkingherefortwentyyears.
Inanothermonth’stimeshe’llhavebeenstudyinghereforthreeyears.
4)将来完成时(由shall/willhave+过去分词构成):将来某时会业已发生的事.
Ishallhavefinishedthisonebeforelunch.
They’llhavehittheyear’stargetbytheendofOctober.