Use the following idea to write a sentence in the passive voice .... "save soap and waste paper"
In a sentence that uses active voice, the subject of the sentence is performing the action. An example using the idea expressed above might be:
If you continue to wash your hands like that, you will save soap but waste paper.
In this active sentence, the subject is "you." You are saving soap and wasting paper. "Soap" and "paper" are direct objects.
To turn this sentence into passive voice, the direct objects become the subjects. Example:
Soap will be saved but paper will be wasted if you continue to wash your hands like that.
In this passive sentence, the subjects are "soap" and "paper" which are being "saved" and "wasted" by you.