Breakdown of Il faut ralentir et être prudent.
être
to be
et
and
il
it (impersonal subject)
falloir
to be necessary / must (impersonal)
Questions & Answers about Il faut ralentir et être prudent.
Why does Il faut translate to "You must" instead of "He must"?
Il faut is an impersonal expression. The il doesn't mean "he" here; it is a placeholder subject like the "it" in "it is raining." It literally means "it is necessary." When translating to English, we usually express this general rule as "you must," "we must," or "one must."
Why do we use the dictionary forms ralentir and être here?
When you want to say "it is necessary to do something," you always follow il faut with an infinitive (the unchanged, unconjugated form of a verb). Because there are two actions connected by et (and), both ralentir (to slow down) and être (to be) stay in the infinitive.
Prudent is an adjective, so it usually has to match a noun. Since there is no specific person here, why is it masculine?
When making a general statement using an impersonal expression like il faut, French defaults to the masculine singular form for adjectives. So we use prudent rather than the feminine prudente or the plural prudents.
If Il faut is general, what if I actually want to say "He must slow down"?