`1. ``has never seen
`2. `remembered / had forgotten
`3.` had sold
`4` You had put / went
`5.` haven't seen
`6. `has done
`7. `realized / had forgotten
`8. `have never seen
`9.` arrived / has just gone
Cấu trcsu :
`=>`QLĐ : S + ved/ cột 2
`=>` HTHT : S + have/jass + Pll