Мы завернули картофель в фольгу и поставили его в духовку.

They are both past tense, plural forms.

• завернули = we wrapped
• поставили = we put / placed

The ending -ли shows that the subject is мы (we), so the action was done by more than one person or by a group including the speaker.

Compare:

• я завернул = I wrapped
• она завернула = she wrapped
• мы завернули = we wrapped

Russian uses the perfective aspect here because the sentence describes completed actions with a result:

1. the potatoes were wrapped,
2. then they were put into the oven.

So:

• завернули is perfective: the wrapping was completed
• поставили is perfective: the placing into the oven was completed

If you used imperfective forms like заворачивали or ставили, it would sound more like describing a process, repeated action, or background action rather than a finished sequence.

The dictionary form is завернуть.

In this sentence, завернуть что-то во что-то / в что-то means to wrap something in something.

Related forms:

• завернуть — perfective
• заворачивать — imperfective

So:

• Мы завернули картофель... = We wrapped the potatoes...
• Мы заворачивали картофель... = We were wrapping / used to wrap the potatoes...

Both words can mean potato / potatoes, but they differ in style.

• картофель is more neutral, standard, or slightly formal
• картошка is more everyday and conversational

So this sentence could also be said as:

• Мы завернули картошку в фольгу...

That would sound a bit more casual and natural in everyday speech.
Using картофель is still completely correct.

In Russian, картофель can be used as a collective or mass noun, similar to how English might say potato in some cooking contexts, but English more often uses potatoes.

So картофель does not necessarily mean just one potato. It can refer to potato as a food item or to potatoes in general, depending on context.

That is why the pronoun later is also singular:

• картофель → grammatical singular
• его = it

Even if English translation uses potatoes, Russian can still keep the noun grammatically singular.

Because фольгу is accusative case, used after в when there is an idea of movement into or a change of state/result.

Here, the potato is being wrapped into foil — the result is that it ends up enclosed in foil.

• фольга = nominative
• в фольгу = accusative

This is a common pattern:

• завернуть рыбу в бумагу = wrap the fish in paper
• положить подарок в коробку = put the gift into a box

By contrast, в фольге would mean in foil as a location or state, not the action of putting/wrapping it there.

For the same reason: в takes the accusative when it means into, showing direction or destination.

• в духовку = into the oven
• в духовке = in the oven

So:

• поставили его в духовку = put it into the oven
• он был в духовке = it was in the oven

This is one of the most important Russian case patterns:

• в + accusative = motion into
• в + prepositional = location in

Его refers back to картофель.

Since картофель is grammatically singular masculine, the pronoun is also singular masculine:

• картофель → его

In the sentence, его is in the accusative case, because it is the direct object of поставили.

So:

• поставили кого? что? → его

Because Russian grammar follows the form of the noun, not the English translation.

Even if you understand картофель as potatoes in context, the noun itself is still grammatically singular masculine, so the pronoun becomes singular too:

• картофель → его

If the sentence used a clearly plural noun, the pronoun would be different. For example:

• Мы завернули картофелины в фольгу и поставили их в духовку.
• Here их is plural because картофелины is plural.

That is a very common learner question. In Russian, поставить is often used more broadly than English set upright.

It can mean put / place something somewhere, especially when placing an object in a location for some purpose.

So in kitchen contexts, Russians often say things like:

• поставить в духовку = put into the oven
• поставить на стол = put on the table

English often uses put, while Russian may choose among:

• положить — put/lay
• поставить — put/set/place
• класть / ставить — imperfective versions

Here поставили в духовку sounds very natural.

Yes, you often could, and it would still be understandable and natural in many contexts.

Very roughly:

• положить focuses more on laying/putting
• поставить focuses more on placing/setting

In real speech, both can be used with food or dishes going into an oven, depending on how the speaker imagines the object and the situation.
In this sentence, поставили is perfectly normal.

Russian has no articles.

English distinguishes between:

• a potato
• the potato
• potatoes
• the potatoes

Russian does not mark that with a separate word. Instead, the meaning is understood from context, word order, and situation.

So картофель could be understood as:

• potato
• the potato
• potatoes
• the potatoes

depending on context.

No, Russian word order is relatively flexible, though this version is very neutral and natural:

• Мы завернули картофель в фольгу и поставили его в духовку.

This gives a straightforward sequence: we → wrapped → the potato → in foil → and put it → into the oven

You could change the order for emphasis, for example:

• Картофель мы завернули в фольгу и поставили его в духовку.

That emphasizes картофель.
But the original order is the most neutral.

Sometimes yes, but keeping it is very natural.

Russian can omit objects in some contexts if they are obvious, but here его helps clearly connect the second action to картофель:

• Мы завернули картофель в фольгу и поставили его в духовку.

Without его, the sentence might still be understood, but it would sound less complete to many speakers:

• Мы завернули картофель в фольгу и поставили в духовку.

That can still work in conversation, especially if the meaning is obvious from context.

Here is a full breakdown:

• Мы — nominative, subject
• картофель — accusative, direct object of завернули
• в фольгу — accusative after в, showing result/direction into
• его — accusative, direct object of поставили
• в духовку — accusative after в, showing motion into

So this sentence is a good example of the accusative case in several roles.

Because it is an inanimate masculine noun, and many such nouns have the same form in nominative and accusative singular.

• nominative: картофель
• accusative: картофель

This is normal for inanimate masculine nouns.

Compare:

• стол → вижу стол
• картофель → завернули картофель

But animate masculine nouns usually change differently:

• брат → вижу брата

So even though картофель is the object, its form stays the same.