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