She's the teacher's pet.

她是老师的宝贝疙瘩。

《牛津词典》

Though she meant well, she was often chastised for being the teacher's pet.

虽然她是好意，可她因为是老师的宠儿而常被惩罚。

youdao

Eg. She never gets in trouble for not doing her homework because she is the teacher's pet.

他是老师的宠儿，所以家庭作业做不做都不要紧。

youdao

But if Spain is to be the good pupil of southern Europe, it also wants to be teacher's pet.

ECONOMIST: The Spanish election

You'll feel like the teacher's pet in one of the Inn's cosy guest rooms, but you aren't here to linger indoors.

BBC: Daily deal: A Florida zip line tour

Then there was the North Yorkshire community school which had turned the Pi into an RFID (radio-frequency identification) reader to measure lap times in their cross-country races, and the London independent school whose pupils had come up with Teacher's Pet, a way of delivering homework via USB sticks plugged into the tiny computer.

BBC: The life of Pi - clever ideas with a tiny computer