`8.` A lot of photographs could be taken (by him) when he was in Spain.

`-` Bị động của động từ khuyết thiếu:

$(+)$ S + modal verb + be + V(pp) + (by O)

`-` take - took - taken

`9.` The newspaper is going to be bought (by me) for my granddad.

`-` Bị động của thì tương lai gần:

$(+)$ S + am/is/are + going to + be + V(pp) + (by O)

`-` buy - bought - bought: mua

`10.` Mary should be invited to the party by Peter.

`-` Bị động của động từ khuyết thiếu

$\Longrightarrow$8.A lot of photographs could be taken when he was in Spain.

$\Longrightarrow$9. The newspaper is going to be bought for my granddad.

$\Longrightarrow$10. Mary should be invited to the party by Peter.

$\Longrightarrow$Form:

+HTTD: S+am/is/are+being+ $P_{II}$ +(by+O)

+HTHT: S+have/has+been+ $P_{II}$ +(by+O)

+QKĐ: S+was/were+ $P_{II}$ +(by+O)

+QKTD: S+was/were+being+ $P_{II}$ +(by+O)

+TLĐ:S+will+be+ $P_{II}$ +(by+O)

+TLG: S+am/is/are+going to+be+ $P_{II}$ +(by+O) 

+Model verb (M): S+M+be+ $P_{II}$ +(by+O)