what do you think__to protect our environment in the past few yea_英语解答

what do you think__to protect our environment in the past few year?
A to do B was done C has been done D have done

人气：422 ℃　时间：2019-10-23 11:50:55

解答

选择 C
应该是一个现在完成时,并且应该用被动语态