5. 150 travel agents were invited to solve holiday problems.

6. They were asked for advice about crossing the Adriatic Sea from Italy to Corfu by a tourist.

7. The letters are collected from the postbox and are taken it to the post office by a postman( ko chắc câu này lăm)

đc bao nhiêu sao cũng đc 

5.150 travel agents were invited to solve some holidap problems.
$\boxed{\text{S+were/was+VpII+(by O)+.....}}$

6.They were asked for advice about crossing the Adriatic Sea from Italy to Corfu by a tourist.
$\boxed{\text{S+were/was+VpII+...(by+O)}}$

7.Letters are collected from the postbox and are taken to the post office by a post man.

$\boxed{\text{S+be+VpII+....(by+O)}}$