Друг купил безделушку.

My friend bought the trinket.

Breakdown of Друг купил безделушку.

• друг: the friend
• купить: to buy
• безделушка: the trinket

Questions & Answers about Друг купил безделушку.

Why does безделушка become безделушку in this sentence?

Because it is the direct object of the verb купил (bought), so it takes the accusative case.

• Dictionary form: безделушка
• Accusative singular: безделушку

This happens because безделушка is a feminine noun ending in -а. For many feminine nouns like this:

• nominative: -а
• accusative: -у

So:

• безделушка = a trinket / knickknack
• купил безделушку = bought a trinket

Why is друг not changing its form?

Because друг is the subject of the sentence, and subjects normally stand in the nominative case, which is the basic dictionary form.

So here:

• друг = the friend / a friend
• купил = bought
• безделушку = a trinket

The subject is the person doing the action, so друг stays in the nominative.

Why is the verb купил and not купила?