Great changes____ in our country during the past 20 years.A.have _英语解答

Great changes____ in our country during the past 20 years.
A.have happened B.happened c.have been happened D.were happened
为什么

人气：480 ℃　时间：2019-08-20 21:53:59

解答

选A
因为happen没有被动,所以C和D被排除
during the past 20 years是过去的一段时间
过去时不能表示这一意思
完成时可以表示
所以选A