1.Thehomeworkfinished,Iwanttohelpmymothercleantheroom.

　　2.Sincethehomeworkisfinished,Iwanttohelpmymothercleantheroom.

　　3.BecauseIhavefinishedthehomework,Iwanttohelpmymothercleantheroom.

　　4.AsIhavefinishedthehomework,Iwanttohelpmymothercleantheroom.

　　5.Iwanttohelpmymothercleantheroom,forIhavefinishedthehomework.

　　6.Iwanttohelpmymothercleantheroom,asIhavefinishedthehomework.

　　7.Iwanttohelpmymothercleantheroom,becaseIhavefinishedthehomework.