French language Q&A Forum

Hi,

In a context outside these lessons, I was asked to put the following sentence in la voix passive:

"Le conducteur n'a pas pu arrêter le train à temps."

I thought it would be straightforward and answered as follows:

"Le train n'a pas été pu arrêter à temps par le conducteur."

But this was marked as false, with the correct answer being:

"Le train n'a pas pu être arrêter à temps par le conducteur."

I don't believe the use of la voix passive with modal verbs (pouvoir, devoir, vouloir) was covered explicitly in this lesson, so I wanted to ask if you could please explain these rules, since it seems they might differ from the rules presented here.

thanks, Scott