Breakdown of É preciso que uses o uniforme adequado.
usar
to use / to wear
que
that (conjunction)
é preciso
it is necessary
o uniforme
the uniform
Questions & Answers about É preciso que uses o uniforme adequado.
Why do we use uses (subjunctive) instead of usas (indicative) here?
The phrase É preciso que (It is necessary that) triggers the subjunctive. Impersonal expressions of necessity show that an action is required or desired rather than a guaranteed fact. Because of this, the following verb (usar) must be in the present subjunctive.
Could I express this same necessity without using the subjunctive?
Yes! If you drop the word que, you use the infinitive instead. For example, you could say É preciso usares o uniforme adequado (using the personal infinitive to specify 'you') or just É preciso usar o uniforme adequado (as a general rule: 'It is necessary to wear...'). The subjunctive is forced here specifically by the combination of É preciso and que.
Why does uses translate to 'wear' in this sentence instead of 'use'?
In Portuguese, the verb usar is very versatile. You use it for tools and objects ('to use'), but it is also the standard verb for clothing, jewelry, makeup, and even hairstyles ('to wear'). Since the context here is a uniform (uniforme), 'wear' is the most natural English translation.
How do we know who is supposed to wear the uniform if there is no pronoun like tu or você?