40. Once harm ______ to the environment, it takes years to have the system recovered.

A. does　　　　　　　　　 B. is done　　　　　　　 　 C. will be done　 　 　　D. be done

39. Staying in a hotel in Shanghai one day costs ____ renting a house in my hometown for a week.

A. the three times price of　　 　　　　　 　B. three times the price of

C. as much as three times　　 　　　　　　　　　　 　D. as much three times as