`bb(Answer) ` 

` 8 ` . This cassette must not be used after ` 5 : 15 ` pm 

` - ` Bị động với động từ khiếm khuyết must : S + must ( not ) be + V3 + ( by O ) 

`9 ` . The first telephone was made a long time ago 

` - ` Bị động thì quá khứ đơn : S + was / were + ( not ) + V3 + ( by O ) 

` 10 . ` An English speaking contest will be held next week 

` - ` Bị động thì tương lai đơn : S + will ( not ) be + V3 + ( by O ) 

8. this cassette musn't be used after 5:15

      musn't + V(b) -> musn't + be + P2

9. the fist telephone was made a long time ago

      Vqk -> was/were+P2

10. an English speaking contest will be hold next week

      will+V(b) -> will +be+P2