Które krzesło jest wygodne?

to be

Breakdown of Które krzesło jest wygodne?

• krzesło: the chair
• wygodny: comfortable
• które: which

Questions & Answers about Które krzesło jest wygodne?

What does które mean in this sentence?

Które is the neuter nominative singular form of the interrogative pronoun który, meaning which. It agrees in gender, number, and case with krzesło, which is neuter singular.

Why is krzesło in the nominative case?

Krzesło is the subject of the sentence—the thing we’re asking about—so it stands in the nominative case.

Why is the verb jest in the singular form?

Because krzesło is singular. Jest is the 3rd person singular of być (to be). If you asked about multiple chairs, you would use the plural są:
Które krzesła są wygodne? (Which chairs are comfortable?)

What kind of word is wygodne, and why does it end with -e?

Wygodne is an adjective in the neuter nominative singular form (agreeing with krzesło). Neuter singular adjectives in nominative end with -e.

Why doesn’t this question start with czy?