1. Nobody can measure the depth of the river
-/> The depth of the river can't be measured
2. They are building a new power plant
-> A new power plant are being built by them .
3. Someone gave her a bunch of flowers
-> A bunch of flowers was given to her
She was given a bunch of flowers
4. We grow rubber trees in our country
-> Rubber trees are grown in our country .
5. I have seen that exciting film many times
-> That exciting film have been seen many times
6. They saw that boy go out
-> That boy was seen go out
7. These boys could do that work
-> That work could be done by these boys.
8. Nobody can explain this problem
-> This problem can't be explained