Утром дедушка ел ватрушку, а я взяла бублик с маслом.

Утром is a very common adverbial use of the instrumental case in Russian. It means in the morning or this morning, depending on context.

Russian often uses certain time expressions without a preposition, especially with parts of the day:

• утром = in the morning
• днём = in the daytime / during the day
• вечером = in the evening
• ночью = at night

So Утром дедушка ел ватрушку means In the morning, Grandpa was eating / ate a vatrushka.

Дедушка is the subject of the first clause, so it is in the nominative case.

Even though дедушка refers to a male person, it ends in -а, which looks like a typical feminine ending. But this is a special noun: it is grammatically declined like a feminine-type noun, while still referring to a male.

So:

• дедушка = nominative singular
• it means grandpa / grandfather
• it agrees with masculine verbs and adjectives when referring to a man

That is why in the past tense you get дедушка ел, not ела.

In the past tense, Russian verbs agree with the subject in gender and number.

• ел = masculine singular past
• ела = feminine singular past
• ело = neuter singular past
• ели = plural past

Since дедушка is male, the verb is ел.

So:

• дедушка ел = Grandpa ate / was eating
• бабушка ела = Grandma ate / was eating

Because the subject in the second clause is я, and the speaker is understood to be female.

In Russian past tense, я does not itself show gender, but the verb does:

• я взял = I took (male speaker)
• я взяла = I took (female speaker)

So а я взяла бублик с маслом tells you that the speaker is female.

They are both direct objects, so they are in the accusative case.

• ватрушка → ватрушку
• бублик → бублик

Why does one change and the other not?

1. ватрушка → ватрушку

This is a feminine noun ending in -а, and feminine nouns usually change in the accusative singular:

• nominative: ватрушка
• accusative: ватрушку

2. бублик → бублик

This is a masculine inanimate noun. In Russian, masculine inanimate nouns often have the same form in nominative and accusative singular:

• nominative: бублик
• accusative: бублик

So both are accusative, even though only one visibly changes.

The preposition с can mean with, and when it has that meaning, it commonly takes the instrumental case.

So:

• масло = butter
• с маслом = with butter

That is why you get:

• бублик с маслом = a bagel/ring-shaped bread with butter

This is a very common pattern:

• чай с сахаром = tea with sugar
• хлеб с сыром = bread with cheese
• кофе с молоком = coffee with milk

In this sentence, а is a contrastive connector. It often means something like:

• and, when contrasting two facts
• whereas
• while
• sometimes almost but

So here:

• Утром дедушка ел ватрушку, а я взяла бублик с маслом.

has the feeling of:

• Grandpa ate a vatrushka, while I took a bagel with butter
• Grandpa had a vatrushka, and I had a bagel with butter instead

Difference from и

И simply adds information: and.

Difference from но

Но is stronger and more clearly means but.

So а is used because the sentence is gently contrasting two people and what each had.

The verbs are from different aspect pairs:

• есть / съесть = to eat
• брать / взять = to take

Here:

• ел is imperfective past
• взяла is perfective past

ел (imperfective)

This can describe:

• an ongoing action
• a repeated/habitual action
• a simple past action when the focus is not on completion

So дедушка ел ватрушку can feel like Grandpa was eating a vatrushka or simply Grandpa ate a vatrushka, depending on context.

взяла (perfective)

This presents the action as completed: the speaker took/picked up/ordered the bagel.

So the contrast may be something like:

• Grandpa was eating / ate
• I took/chose a bagel with butter

Yes, взяла literally means took, but in food contexts Russian often uses взять in a broader sense:

• to take
• to choose
• to get
• to have
• to order

So я взяла бублик с маслом can mean:

• I took a bagel with butter
• I got a bagel with butter
• I chose a bagel with butter

It does not necessarily mean the speaker already ate it. The focus is on choosing or taking it.

A ватрушка is a traditional Russian pastry, usually a round bun with an open center filled with something like:

• творог (farmer’s cheese / curd cheese)
• jam
• sometimes other fillings

It is a cultural vocabulary item, so many learners ask about it because there is no perfect one-word English equivalent.

Бублик is a ring-shaped bread product, somewhat similar to a bagel, though not always identical in texture or cultural use.

In learner translations, bagel is often used because it is the closest familiar English word. But depending on region and context, бублик may suggest a slightly different kind of baked ring bread.

Because the sentence has two clauses, each with its own subject and verb:

1. дедушка ел ватрушку
2. я взяла бублик с маслом

They are joined by а, and in Russian such clauses are normally separated by a comma.

So the comma is standard punctuation here.

Yes. Russian word order is quite flexible, though different orders create different emphasis.

The neutral version here is:

• Утром дедушка ел ватрушку, а я взяла бублик с маслом.

Possible alternatives include:

• Дедушка утром ел ватрушку, а я взяла бублик с маслом.
• Утром ватрушку ел дедушка, а я взяла бублик с маслом.

These all mean roughly the same thing, but the emphasis shifts:

• putting утром first highlights the time
• putting ватрушку earlier can highlight what was eaten
• keeping я after а gives a natural contrast: as for me / while I...

Russian has no articles. It does not have separate words corresponding exactly to a/an and the.

So:

• дедушка can mean grandpa or the grandpa, depending on context
• ватрушку can mean a vatrushka or the vatrushka
• бублик can mean a bagel or the bagel

Russian expresses definiteness through context, word order, stress, and shared knowledge instead of articles.

Yes. Утром can mean either:

• in the morning as a general time frame
• this morning in the right context

Russian often leaves that distinction to context. So depending on the situation, the sentence could be understood as:

• In the morning, Grandpa ate a vatrushka, and I took a bagel with butter
• This morning, Grandpa ate a vatrushka, and I took a bagel with butter

Both are possible.