Sep 28, 2022 - 09:37 AM
Here this is not a passé composé but a passive form in the present, just like in English, we're not saying that she replaced someone, but that she IS replaced during the summer, hence the use of être/to be, just like in English.
In the passé composé, you're right that we would need "avoir": Elle a remplacé son collègue pendant l'éte´= She replaced her colleague during the summer..
Hope this helps!
Enjoy the program!