`1.` Their car has been sold to pay their debts.

`-` HTHT : S + have/has been + P2 by O

`2.` The English grammar has been explainted by our teachers .

`-` HTHT : S + have/has been + P2 by O

`3.` The pollution prolems have been discussed by the students since last week.

`-` HTHT : S + have/has been + P2 by O

`4.` How many languages are spoken in Canada?

`-` HTĐ : S + am/is/are + P2 by O

`5.` Has the secretary been phoned by the manager this morning?

`-` HTHT : S + have/has been + P2 by O

`6.` Has this room been kept since last Sunday?

`-` HTHT : S + have/has been + P2 by O

`7.` Has Tim been shown the spencial cameras?

`-` HTHT : S + have/has been + P2 by O

`-` BĐNV `-` HTĐ : Is / Am / Are + S + VpII ( by O ) ?

`-` BĐ `-` HTHT :

`+` KĐ : S + have / has + been + VpII ( by O )

`+` PĐ : S + haven't / hasn't + been + VpII ( by O )

`=>` `DHNB` : since , for , already , ...

`1`.Their car has been sold to play their debts

`2`.The English grammar has been explained by our teachers

`3`.The pollution problems have been discussed by the students since last week

`4`.How many languages are spoken in Canada ?

`5`.Has the secretary been phoned by the manager this morning ?

`6`.Has this room been kept since last Sunday ?

`7`.Has Tim been shown the special cameras ?

`\text{# TF}`