23. Mary has not written to her close friend for 2 months

- S have/has not VPII

24. A story is going to be told by the teacher

- S tobe going to be VPII by O

25. The last time I went shopping was 2 months ago

- The last time QKD was ...

26. The boy is believed to be wearing a white T-shirt and blue jeans

- S tobe VPII to V

`23`. Mary has not written to her close friend for 2 months

`→`  The last time +S + Ved/2 + was + time + ago = S + have / has not + Ved/3 + for + time 

`24`. A story is going to be told by the teacher

`→` Bị động thì TLG

`25`. The last time I went shopping was 2 months ago

`→` S + haven't + Ved/3 + for + time  = The last time +S + Ved/2 + was + time + ago  

`26`. The boy is believed to be wearing a white T-shirt and blue jeans

`→` It + be + Ved/3 + that + S+ $V_{2}$ = S + be + Ved/3 + to be + $V_{2}$