48.What can we know about Mr.Stone? A.He is a doctor in the Army now. He is going to give up his work. He knows a lot about the city the author is going to. He has been retired for many years. 49.The writer calls the second person "Grandmother" because ___. A.she looks oldB.she has three daughters C.he respects herD.he can't think of her name 50.The underlined phrase "on leave" (in Paragraph 4) means "____. A.about to goB.on vacationC.leavingD.at home