English Idioms: X marks the spot.

English Idioms About “Nature”
Idiom: Gain ground
Meaning: To become popular, to make progress, to advance.
Example: The new product gained ground in a very short time.

English Idioms About “Relationship”
Idiom: Fair-weather friend
Meaning: Someone who is your friend only when the times are good.
Example: Don’t rely on him.He’s a fair-weather friend.

English Idioms About “Colors”
Idiom: All cats are grey in the dark
Meaning: The phrase all cats are grey in the dark means that in the dark, physical appearance is unimportant. The phrase is attributed to Benjamin Franklin.
Example: I really don’t care if she is ugly. All cats are gray in the dark.

English Idioms About “Men and women”
Idiom: To a man
Meaning: The idiom to a man means without exception.
Example: All the neighbors were present at the meeting and they all, to a man, agreed to help the poor family.

English Idioms About “Food”
Idiom: Hot potato
Meaning: An awkward or delicate problem with which nobody wants to be associated.
Example: Gun control in the United States has always been a hot potato for politicians.