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