现在完成时的被动语态
[观察例句]
1．Much has been written about the Great Wall.
2．Many people have been helped by the club.
3．Jan's life has been greatly improved by the Internet.
4．Look at the way your face has been washed.
5．Today I thought I'd answer a question that has been asked many times—how do you stay safe online and avoid bad experiences on the Internet?
