A leopard can't ... its spots.
A leopard can't change its spots.
It's a ... of cake.
It's a piece of cake.
Burn the ... oil.
Burn the midnight oil.
Feeling ... the weather.
Feeling under the weather.
... the hook.
Off the hook.
Cross that ... when you come to it.
Cross that bridge when you come to it.
As ... as a rock.
As solid as a rock.
... your tongue.
Bite your tongue.
Take it with a ... of salt.
Take it with a grain of salt.
Every cloud has a ... lining.
Every cloud has a silver lining.
Curiosity ... the cat.
Curiosity killed the cat.
Bite off more than you can ....
Bite off more than you can chew.
Actions ... louder than words.
Actions speak louder than words.
Don't put all your eggs in one ....
Don't put all your eggs in one basket.
The ball is in your ....
The ball is in your court.
Close, but no ....
Close, but no cigar.
Once in a ... moon.
Once in a blue moon.
She's a ... horse.
She's a dark horse.
At the ... of a hat.
At the drop of a hat.
It's a ... in the bucket.
It's a drop in the bucket.
... on the bandwagon.
Jump on the bandwagon.
The best thing since ... bread.
The best thing since sliced bread.
It's a ... in disguise.
It's a blessing in disguise.
Let ... dogs lie.
Let sleeping dogs lie.
Sit on the ....
Sit on the fence.
I'll be glad to see the ... of him.
I'll be glad to see the back of him.
I ... a rat.
I smell a rat.
Kill ... birds with one stone.
Kill two birds with one stone.
It's the ... of both worlds.
It's the best of both worlds.
... the hatchet.
Bury the hatchet.
You're ... up the wrong tree.
You're barking up the wrong tree.
Let's ... the knot.
Let's tie the knot.