Usages of se plaindre de
Le psychologue se méfie de ce dont tu te plains.
The psychologist is wary of what you are complaining about.
Ils se plaignent souvent du comportement de leur ami.
They often complain about their friend's behavior.
Le col de cette veste est sale, il s'en plaint.
The collar of this jacket is dirty, he complains about it.
Elon.io is an online learning platform
We have an entire course teaching French grammar and vocabulary.