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 strong as an ox.
If someone is as strong as an ox they are extremely strong and have great physical strength.
E.g. Ask John to help you move the office furniture. He’s as strong as an ox. It will be easy for him.
As keen as mustard.
If someone is as keen as mustard they are very eager, enthusiastic and excited (about or to do something).
E.g. He’s still not the most skillful footballer but he’s as keen as mustard. He’s always the first one to arrive at training and the last one to leave.
As nutty as a fruitcake.
If someone is as nutty as a fruitcake they are crazy, idiotic or wacky.
E.g. He always comes up with the craziest ideas. They never work. Take no notice of him – he’s as nutty as a fruitcake.
Have fun learning English!
Louise