The joke is as old as...
the hills
That's as clear as...
mud
We got on like...
a house on fire
I've got a memory like...
a sieve
They are like chalk and...
cheese
My mother never gets stressed, she's always as cool as...
a cucumber
Without my glasses I'm as blind as...
a bat
My mum's got eyes like...
a hawk
It's as dead as...
a dodo
I felt like a fish...
out of water
I'm so happy today, like...
a dog with two tails
She went as white as ...
a sheet
He's as hard as...
nails
My brother is as strong as...
a horse