“I __have explained__(explain) this to you several times already,”said the teacher.“I hope you ___have understood_____（understand) it now.”Then he looked at a little boy at theback of the class.“____Have you been ___ you ___istening____(listen),Jones?”he asked.“Here is a simple problem:"Sally _____has_worked（work) in an office f...
have explained…have understood…Have you been listening…has been working/ has worked…has been earning/ has earned…has she earned…have not been listening...
