know one's ABCs
знать основное о чём-либо, иметь базовые знания
The woman in the library knew her ABC's and could quickly give me the information I needed.
Другие идиомы:
- know (something) only too well
- not know if one is coming or going
- know which is which
- know (something) inside out
- know the score
- know-how
- know one's stuff
- know the ropes
- know better (than to do something)
- know when one is not wanted
- know what's what
- know (something) backwards and forwards
- know which side one's bread is buttered on
- know-it-all
- know where (someone) stands on (something)