"Voler" means "to fly." And "en" means "in," while the s' is the reflexive. Yet, "s'envoler" means to fly away, which is different from what I would expect, reading the above. (And google translate ...
All verbs that take "être" as their auxiliary verb must agree in gender and number with the subject. This I know. But does this apply also to pronominal verbs? For instance, "Elle s'est rasée les ...
Why do we use a s' in this sentence: La fenêtre ne s'ouvre pas ! Is it because of the two vowels or for the type of verb?