Questions & Answers about Bieżnik jest dobry, a układ kierowniczy i klakson są sprawne.
In this sentence, bieżnik means the tire tread—the patterned outer part of a tire that touches the road.
A useful note: bieżnik can mean other things in other contexts, but in car-related language it usually means tread.
They can both be translated as and, but they are used differently.
- i simply joins words or phrases: układ kierowniczy i klakson = the steering system and the horn
- a joins two clauses and often suggests a slight contrast, shift, or comparison: Bieżnik jest dobry, a... = The tread is good, and/as for...
So here:
- a connects the first statement to the second
- i connects the two things inside the second subject
Because the subject changes from singular to plural.
- bieżnik is singular, so you use jest = is
- układ kierowniczy i klakson is a compound subject with two things, so it is plural, and you use są = are
So:
- Bieżnik jest dobry = The tread is good
- Układ kierowniczy i klakson są sprawne = The steering system and the horn are functional