scratch one's back
To do something kind and helpful for someone or to flatter him in the hope that he will do something for you. Usually used in the expression You scratch my back and I'll scratch yours.
Mary asked Jean to introduce her to her brother. Jean said, "You scratch my back and I'll scratch yours."
scratch the surface
To learn or understand very little about something. Usually used with a limiting adverb (as only, hardly).
We thought we understood Africa but when we made a trip there we found we had only scratched the surface.
High school students have only scratched the surface of their subjects, and even after college graduation, they still find there is much more to learn.
second-rate
Of mediocre or inferior quality.
The movie received a bad review; it was second-rate at best.
separate the men from the boys
To show who has strength, courage and loyalty and find who do not.
When the ship hit an iceberg and sank, it separated the men from the boys.
The mile run separates the men from the boys.
separate the sheep from the goats
Отделить овец от козлищ.
Examining job applications is the first stage in separating the sheep from the goats.
Просмотр заявлений о приеме на работу – это первая стадия отбора.
smell a rat
To be suspicious; feel that something is wrong.
Быть подозрительным; чувствовать, что что-то происходит не правильно.
Every time Tom visits me, one of my ashtrays disappears. I'm beginning to smell a rat.
When the policeman saw a light go on in the store at midnight, he smelled a rat.
Detectives went to the hotel to meet the drug dealers, but the dealers must have smelled a rat, and they stayed away.
Детективы пошли в отель, чтобы встретиться с наркодилерами, но те, вероятно, почувствовали неладное и не пришли.
up to par
up to the mark
up to scratch
up to snuff
In good or normal health or physical condition.
I have a cold and don't feel up to par.
The boxer is training for the fight but he isn't up to scratch yet.
As good as usual; up to the usual level or quality.
The TV program was not up to par tonight.
John will have to work hard to bring his grades up to snuff.
vibrations
vibes
Psychic emanations radiating from an object, situation, or person.
I don't think this relationship will work out - this guy has given me bad vibes.