Лікар оглянув легеню.

Because легеню is the accusative singular form of легеня (lung).

In this sentence, легеня is the direct object: it is the thing the doctor examined. In Ukrainian, direct objects often take the accusative case.

For this feminine noun pattern:

• легеня = nominative singular
• легеню = accusative singular

So:

• Легеня здорова. = The lung is healthy.
• Лікар оглянув легеню. = The doctor examined the lung.

Лікар is in the nominative singular.

It is the subject of the sentence, the person doing the action. The nominative is the basic dictionary form for nouns when they are the subject.

So here:

• лікар = the doctor
• оглянув = examined
• легеню = the lung

You know mostly from the case endings, not just from word order.

• лікар is nominative, so it is the subject
• легеню is accusative, so it is the object

That is why Ukrainian can sometimes change word order more freely than English.

In this sentence, the roles are clear because of grammar:

• Лікар = the one who examined
• легеню = the thing examined

Оглянув is the past tense of оглянути, meaning examined, inspected, or looked over.

In a medical context, оглянув is very naturally translated as examined.

So the sentence means that the doctor completed an examination of the lung.

Because оглянув is a masculine singular past tense form.

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

Here the subject is understood as masculine, so:

• оглянув = masculine singular
• оглянула = feminine singular
• оглянуло = neuter singular
• оглянули = plural

So this sentence specifically presents the doctor as male, or at least uses masculine agreement.

The most straightforward version would be:

Лікарка оглянула легеню.

That uses:

• лікарка = female doctor
• оглянула = feminine past tense

You may also sometimes see a feminine verb with лікар, depending on style and context, but for a learner, лікарка оглянула легеню is the clearest pattern.

It is perfective.

That means it presents the action as completed: the doctor examined the lung and finished doing so.

The imperfective equivalent would be something like оглядав, which would suggest:

• was examining
• used to examine
• examined in a more process-focused sense

So оглянув is a good choice for a completed, one-time action.

Yes. Ukrainian word order is more flexible than English because case endings show grammatical roles.

The most neutral order here is:

Лікар оглянув легеню.

But you could also say:

Легеню оглянув лікар.

That still means the same basic thing, but it gives more emphasis to легеню or creates a different information focus.

So word order can change, but the neutral learner-friendly version is the one you were given.

Because Ukrainian has no articles.

English uses a/an and the, but Ukrainian does not. Whether something is understood as a doctor or the doctor, a lung or the lung, depends on context.

So:

• Лікар can mean a doctor or the doctor
• легеню can mean a lung or the lung

The translation chooses whichever sounds most natural in context.

A good stress pattern is:

ліка́р огляну́в леге́ню

A rough English-style approximation is:

lee-KAR oh-hlya-NOOV leh-HE-nyu

A few helpful notes:

• г in Ukrainian is usually like a voiced h, not a hard English g
• я in оглянув gives a hlya sound
• ню in легеню is soft: nyu

You do not usually write stress marks in normal Ukrainian text, but they are helpful for learners.

It is singular: one lung.

The dictionary form is:

• легеня = lung

The plural is:

• легені = lungs

So:

• Лікар оглянув легеню. = The doctor examined the lung.
• Лікар оглянув легені. = The doctor examined the lungs.

Yes. Without context, that is also possible.

Because Ukrainian has no articles, this sentence could correspond to several English versions, including:

• The doctor examined the lung.
• A doctor examined the lung.
• The doctor examined a lung.
• A doctor examined a lung.

The exact English translation depends on context, not on extra words in the Ukrainian sentence itself.