1.Shehasbeenworkingonherprojectforthepastthreehours.
2.Theyhavebeenstudyingfortheirexamsallday.
3.IhavebeenwatchingTVforthelasthour.
4.Hehasbeencleaninghisroomsincethismorning.
5.Wehavebeenwaitingforthebusforovertwentyminutes.
6.Thedoghasbeenplayinginthebackyardallafternoon.
7.Thechildrenhavebeenrunningaroundandplayingoutside.
8.Shehasbeenpracticingthepianofortherecitalnextweek.
9.Theyhavebeencookingdinnerforthefamily.
10.Ihavebeenreadingthisbookforthepastfewdays.
11.Theworkershavebeenbuildingthehouseforseveralweeksnow.