48. We object _____ carrying out the plan. [(A)] for [(B)] to be [(C)] about [(D)] to

51. Samuel Preston’s study shows that __________. [(A)] lifestyles and responsibilities of the elderly are not changing [(B)] most American couples over 40 have no living parents [(C)] middle-aged Americans have to take care of their children and parents at the same time [(D)] elderly people may need care for a long time because they live longer after an illness