12.My books were taken away.(bị động thì QKD)
13.The wall is cleaned before it is painted.(bị động thì HTD)
14.The wall was cleaned before it was painted.(QKD)
15.John was visited by Mr.Cole at the weekend.(QKD)
16.John is usually visited by Mr.Cole at the weekend.(HTD)
17.John has been visited by Mr.Cole many times.(HTHT)