单项选择题
A.The role of travel agents. B.The way people travel. C.The number of last-minute bookings. D.The prices of polar expeditions.
A.their students work harder B.they recruit the best students C.their classes are generally smaller D.they give students more attention
A.There are a wide range of cases. B.They are very destructive. C.There has been a rise in such crimes. D.They have aroused fear among the residents.