Question

no entiendo el PASSIVE VOICE, se supone que se usa el past participle como verbo, pero supongo que solo cuando una frase esta en pasado, entonces por que esta frase es asi active voice"we don´t clean our rooms" pasive voice "our rooms AREN'T cleaned" por qué NO es " our room WEREN'T cleaned" como que se combina presente con pasado.
en esta no se por qué se usa wasn't en pasado y luego repair, en presente (al revez de la antes mencionada) active voice"william didn't repair the car" passive voice"the car WASN´T repair by william"
HELP!

Answer 1

Because in "we don't clean our rooms" don't is used for present simple. but didn't is used for past simple. So when, it is don't or doesn't, you can use isn't or aren't.
And when it is didn't, you should use wasn't or weren't.