There are many expressions commonly used in English with the comparison form ‘as … as’.
There is no magic rule to help you remember them. You just have to learn them. Sorry!
Take a look at the examples below.
As old as the hills.
If something is as old as the hills it is extremely old, dating from the remote past. It also describes something of long standing.
E.g. That story is as old as the hills. I’ve heard it a hundred times. I’m still not sure it’s true.
As cold as ice.
If you feel as cold as ice you are feeling extremely cold.
E.g. After playing outside in the snow without wearing coats the children were as cold as ice.
It can also describe a person who is lacking emotion or empathy.
E.g. After all the bad things that have happened to her recently you would have to be as cold as ice not to feel sorry for her.
As stubborn as a mule.
If someone is as stubborn as mule they are very sure of their opinion and are determined to do what they think is right. They are unwilling to change their mind, opinion or attitude.
(This expression often shows disapproval.)
E.g. She asked him several times to change the presentation to include more information for the client but he refused. He’s as stubborn as a mule.
Have fun learning English!
Louise