Questions & Answers about É bom que vocês usem menos plástico.
Why is the verb usem instead of the normal present tense usam?
The phrase É bom que (It's good that) expresses a personal opinion or value judgment. In Portuguese, these types of impersonal expressions require the Present Subjunctive for the action that follows. That's why the regular present tense usam changes to the subjunctive usem.
How is the subjunctive form usem created here?
For regular -ar verbs like usar, the Present Subjunctive swaps the usual a vowels for e vowels in its endings. To form it, take the 'I' form of the present tense (uso), remove the -o, and add the subjunctive ending for vocês, which is -em. This gives us usem.
If we were talking about a feminine word like 'water' (água), would menos change to match it?
I've seen vós used for 'you' (plural). Why does this sentence use vocês?