Byť – past tense
Affirmative:

• ja bol – I was (m.)
• ja bola – I was (f.)
• ty bol/-a – you were (sing. informal)
• on bol – he was
• ona bola – she was
• my boli – we were
• vy boli – you were (sing. formal, and plural)
• oni boli – they were
• ony boli – they were (group of females)

Negative:

• ja nebol – I was not (m.)
• ja nebola – I was not (f.)
• ty nebol/-a – you were not (sing. informal)
• on nebol – he was not
• ona nebola – she was not
• my neboli – we were not
• vy neboli – you were not (sing. formal, and plural)
• oni neboli – they were not
• ony neboli – they were not (group of females)

Examples:

• Jeho stolička nebola dostatočne vysoká. – His chair was not high enough.
• Ten náš kolega bola v pondelok poobede taký pracovitý. – That (female) colleague of ours was so hard-working on Monday afternoon.