1.We usaully clean the floor after school.
-> The floor is usually cleaned after school.

2.She is preparing a small party in the garden.
-> A small party is being prepared in the garden.

3.They have just finished their task.
->Their task has just been finished.

4.No one can solve thi problem.
->The problem can be sloved by no one.

5.My students bought lot of sweet last sunday.
->A lot of sweet were bought by my students last sunday.

6.He will build a new swimming pool near our school next year
-> A new sswimming pool will be built near our school next year