Be (as) stubborn as a mule phrase informal simile
Be extremely stubborn
Mina is as stubborn as a mule. She doesn't like broccoli and she won't eat it even if you pay her.
She won't do what you tell because she's as stubborn as a mule.
The boy is as stubborn as a mule. He is bent on buying that motor.
Used to describe someone who is realistic and determined
The verb "be" should be conjugated according to its tense.
To be in a difficult situation or get into trouble
We broke the vase. We are in deep water.