“A needle in a haystack”

“In hot water”

In trouble.

“In the same boat”

In the same situation as others.

“Once in a blue moon”

Very rarely.

“In a nutshell”

In a very brief and clear way.

“A blessing in disguise”

Something that seems bad but turns out good.

“Up in the air”

Not decided yet; uncertain.

“Rome wasn’t built in a day”

Important things take time.

“Don’t put all your eggs in one basket”

Don’t risk everything on one plan.