Она пригласила друзей.

Because it is past tense feminine singular.

In Russian past tense, the verb agrees with the subject in gender and number:

• он пригласил = he invited
• она пригласила = she invited
• оно пригласило = it invited
• они пригласили = they invited

So with она, you need пригласила.

The dictionary form is пригласить.

That is the infinitive, meaning to invite.

So:

• пригласить = to invite
• пригласила = invited (feminine subject)

This verb is perfective, which means it presents the action as a completed whole.

Because друзей is the correct form for the direct object here.

The noun друг means friend. Its plural nominative form is:

• друзья = friends

But in this sentence, friends are being invited, so the word is a direct object. Since друзья refers to people (animate nouns), Russian uses the accusative plural, and for animate masculine nouns that form is the same as the genitive plural:

• nominative plural: друзья
• accusative plural: друзей

So:

• Друзья пришли. = The friends arrived.
• Она пригласила друзей. = She invited friends / her friends / the friends.

Because for animate masculine nouns, the accusative often matches the genitive.

This is one of the most important Russian patterns to learn:

• animate masculine singular: accusative = genitive
• animate plural: accusative = genitive

Examples:

• Я вижу друга. = I see a friend.
  (друга = accusative singular, same as genitive singular)

• Я вижу друзей. = I see friends.
  (друзей = accusative plural, same as genitive plural)

So in your sentence, друзей is functioning as an accusative, even though it looks like a genitive form.

Пригласила is perfective because it describes the invitation as a completed event: she invited them.

If you used приглашала, that would be the imperfective verb приглашать, which can suggest:

• an ongoing process
• repeated action
• background action
• focus on the activity rather than the result

Compare:

• Она пригласила друзей. = She invited her friends.
  (a completed action)

• Она приглашала друзей. = She was inviting friends / used to invite friends / invited friends repeatedly, depending on context

In a simple one-time event, пригласила is the natural choice.

Yes. This is a very normal, neutral word order:

• Она = subject
• пригласила = verb
• друзей = object

Russian word order is more flexible than English because endings show grammatical roles. But changing the order usually changes emphasis, not the basic meaning.

For example:

• Она пригласила друзей. = neutral
• Друзей она пригласила. = emphasizes friends
• Она друзей пригласила. = also possible, with a different rhythm or focus

So the given sentence is a standard, straightforward version.

Yes, very often.

Russian often omits subject pronouns when the subject is clear from context:

• Пригласила друзей. = Invited friends / She invited friends

Because пригласила is feminine singular past tense, a listener can often understand that the subject is she.

Still, она may be included when:

• the subject is being introduced
• there is contrast
• the speaker wants extra clarity or emphasis

So both are possible:

• Она пригласила друзей.
• Пригласила друзей.

Not always. Она can also mean it for a feminine noun.

Russian pronouns reflect grammatical gender, so if you are referring back to a feminine noun, you use она.

But in this sentence, with a human subject, learners normally understand it as she.

Because Russian has no articles.

Russian does not have direct equivalents of English a/an and the. Whether друзей means:

• friends
• the friends
• some friends
• her friends

depends on context.

If you want to make it clearer, Russian can add other words, for example:

• Она пригласила своих друзей. = She invited her friends.
• Она пригласила нескольких друзей. = She invited several friends.

But without extra context, друзей is just the normal Russian way to say it.

Yes, very easily.

Russian often leaves possession unstated when it is obvious from context. So Она пригласила друзей can naturally be understood as She invited her friends, even though there is no separate word for her.

If the speaker wants to stress that they were specifically her own friends, they can say:

• Она пригласила своих друзей.

But the shorter version is very common.

A helpful pronunciation guide is:

• Она → a-NA
• пригласила → pree-gla-SEE-la
• друзей → droo-ZEY

The main stresses are:

• она́
• пригласи́ла
• друзе́й

A few useful notes:

• Unstressed о often sounds closer to a
• The stressed syllable is very important in Russian
• ей in друзей sounds roughly like ey in they, but not exactly the same

Yes. The noun друг is grammatically masculine in the singular, and its plural forms are used for friends in general.

A group called друзья or друзей can be:

• all male
• mixed male and female
• sometimes even informal for a general group of friends

If you specifically want to say female friends, Russian often uses:

• подруги = female friends
• подруг = female friends (object form in some contexts)

So друзей does not necessarily mean only male friends. Context decides.