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