Breakdown of Ils sont en train de préparer le béton.
ils
they (masculine/mixed)
préparer
to prepare
être en train de
to be in the middle of (doing)
le béton
the concrete
Questions & Answers about Ils sont en train de préparer le béton.
Why use sont en train de préparer instead of just préparent?
In French, the simple present tense Ils préparent usually translates to both "They prepare" and "They are preparing." However, if you want to emphasize that an action is happening right at this very exact moment, you use the phrase être en train de plus an infinitive. It's the equivalent of saying "They are in the middle of preparing."
How exactly is the être en train de structure built in this sentence?
Why is préparer left in the infinitive instead of being conjugated?
This is a strict rule in French: whenever a verb immediately follows a preposition (in this case, the de in en train de), it must be in the infinitive form. Other common prepositions that trigger this rule include à, pour, and sans.