Learn Russian: Члены клуба давали одни обещания.

When the plural forms of один (like одни) are placed directly before a noun, they often act as a restrictive particle meaning 'only' or 'nothing but'. In this context, одни обещания emphasizes that they gave 'nothing but promises' and zero action.

What case is одни обещания in?

It is in the accusative case because it is the direct object of the verb давали (they gave). Because обещание (promise) is an inanimate neuter noun, its accusative plural is identical to its nominative plural. The word одни changes to match this case and number.

Why is the imperfective verb давали used here instead of the perfective дали?

Using the imperfective давали shows that this was a repeated or ongoing behavior. The club members were continuously giving promises over time, rather than just making a promise on a single, completed occasion.

Why does клуб end in an 'a' here (клуба)?

It is in the genitive case, which is used to show belonging or association, working just like the English word 'of'. Therefore, Члены клуба translates literally to 'members of the club'.