Сегодня утром я включил тостер, а сестра — кофеварку.

Включил is the masculine singular past tense form of включить.

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

• я включил = I turned on if the speaker is male
• я включила = I turned on if the speaker is female

So this sentence suggests that the speaker is male. If a woman were saying it, she would normally say:

Сегодня утром я включила тостер, а сестра — кофеварку.

Both тостер and кофеварку are direct objects of the verb включить, so they are in the accusative case.

The reason they look different is that different noun types change differently in the accusative:

• тостер is a masculine inanimate noun
  
  • nominative: тостер
  • accusative: тостер
• кофеварка is a feminine noun ending in -а
  
  • nominative: кофеварка
  • accusative: кофеварку

So the sentence shows a very common pattern:

• masculine inanimate nouns often stay the same in the accusative
• feminine -а nouns usually change -а → -у

The dash shows that the verb is being left out because it is understood.

The full sentence would be:

Сегодня утром я включил тостер, а сестра включила кофеварку.

But Russian often omits repeated words when the meaning is clear. Here, the verb включила / включил(а) is understood from the first part.

So:

• я включил тостер
• а сестра — кофеварку

means something like:

• I turned on the toaster
• and my sister [turned on] the coffee maker

The dash marks this omission clearly in writing.

А often connects two parts that are being compared or contrasted, even if the contrast is mild.

Here, the idea is:

• I turned on the toaster
• whereas my sister turned on the coffee maker

So а works well because it sets the two subjects side by side.

Roughly:

• и = and simply adds information
• но = but shows a stronger contradiction
• а = and / while / whereas with a contrast or comparison

In this sentence, а is the most natural choice because the two people did similar but different things.

Включить means to turn on, switch on, or start a device or appliance.

So it is a natural verb for things like:

• включить свет = turn on the light
• включить телевизор = turn on the TV
• включить кофеварку = turn on the coffee maker

With appliances, it usually means activating them so they begin working.

Включить is the perfective partner of включать.

Russian aspect matters a lot:

• включать = imperfective, focuses on process, repetition, or general action
• включить = perfective, focuses on a single completed action

Here the speaker is talking about a specific completed event this morning, so perfective is natural:

• Сегодня утром я включил тостер...
  = This morning I turned on the toaster...

If you used the imperfective, it would sound more like repeated action, background description, or process in the right context.

Russian word order is flexible, and putting the time expression first is very natural when setting the scene.

Сегодня утром means this morning / today in the morning and gives the time frame before the action.

Russian often puts time words near the beginning:

• Сегодня утром я включил тостер...
• Вчера вечером мы смотрели фильм.
• Завтра я поеду в Москву.

This is not the only possible order, but it is a very common and natural one.

Утром by itself means in the morning and can refer to a morning in general or a morning understood from context.

Сегодня утром is more specific: this morning.

So:

• Утром я пью кофе. = I drink coffee in the morning. / In the morning, I drink coffee.
• Сегодня утром я включил тостер. = This morning I turned on the toaster.

Adding сегодня makes the time reference specific.

In Russian, possessive words like мой / моя are often omitted when the relationship is obvious from context.

So сестра here is very naturally understood as my sister, especially because the sentence begins with я and talks about the speaker’s morning.

Russian often does this with family members and personal items when ownership is clear:

• Мама дома. = Mom is at home.
• Брат учится в Москве. = My brother studies in Moscow.

If the speaker wanted to emphasize it, they could say:

а моя сестра — кофеварку

But it is not necessary.

Russian has no articles.

That means Russian does not have direct equivalents of a/an and the as ordinary words before nouns. Whether something is definite or indefinite is understood from:

• context
• word order
• common sense
• emphasis

So тостер can mean:

• a toaster
• the toaster

and кофеварку can mean:

• a coffee maker
• the coffee maker

In this sentence, the exact English article depends on the context, not on a separate Russian word.

You do not say a word for the dash. You simply make a slight pause.

So aloud, the sentence sounds like:

Сегодня утром я включил тостер, а сестра ... кофеварку.

with a pause after сестра.

The listener understands that the missing verb is the same idea as in the first part.

Yes. That is the full version, and it is completely correct.

However, Russian often prefers the shorter version when the repeated verb is obvious:

• Сегодня утром я включил тостер, а сестра — кофеварку.

This sounds neat and natural. The omitted verb is especially common when comparing two people, two objects, or two actions in parallel structure.

It mainly creates a parallel contrast between both:

• я ↔ сестра
• тостер ↔ кофеварку

The structure suggests:

• I turned on the toaster
• my sister turned on the coffee maker

Because of а and the dash, the sentence feels balanced and contrastive. It highlights that the two people did similar actions, but with different appliances.