Pairs often confused
pendant que or alors que in French?
Pendant que states TIME only; alors que adds an OPPOSITION between the two facts.
Why
"Il révise pendant que sa sœur dort" places two actions in the same moment, with no judgement. "Alors que" sets them against each other, and the reader hears a contrast, sometimes a reproach. Both take the indicative; meaning, not mood, separates them.
pendant que
Pendant que les travaux durent, l'accès se fait par la cour.
While the works last, access is through the courtyard.
alors que
Les inscriptions progressent en ligne, alors qu'elles reculent au guichet.
Registrations are rising online, whereas they are falling at the counter.