Być is irregular and worth memorising outright: jestem, jesteś, jest, jesteśmy, jesteście, są. Unlike Russian it is never dropped in the present tense - Polish always says it.
Examples
- Jestem głodny.
- I'm hungry.
- Czy jesteście gotowi?
- Are you ready?
- To jest bardzo dobre.
- This is very good.
The mistake to avoid
Jest is he/she/it; są is they - the two are not interchangeable.
Where this fits in
Food & ordering, Polish A1: Order at a café or restaurant, ask for the bill, and talk about basic food and drink.