Eric, your homework was: 
              (Why cleaning our house is important?)

UNless we clean the room, it can have some dirt. If there is dirt, we can have virus. Virus make us hurt.

Let's rephrase your sentences.

* Cleaning is important to remove dirt in our house. If there is dirt, virus can easily attack us and harm us.

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Eric, take note of this:

* Never start your statement with a negative form and with a conjunction. 

Conjunction is a connecting word in a sentence like, "and", "because", "unless", "but",and etc.