La infano frapas la pordon antaŭ ol ŝi eniras.

Because la pordon is the direct object of frapas.

In Esperanto, the direct object usually takes the accusative ending -n:

• La infano frapas la pordon. = The child knocks on the door / literally hits the door
• La infano vidas la pordon. = The child sees the door

English uses word order to show the object, but Esperanto often shows it with -n.

This is a normal Esperanto pattern. The verb frapi literally means to strike, hit, knock, and the thing being struck is the direct object.

So:

• frapi la pordon = to knock on the door
• literally: to strike the door

English prefers knock on, but Esperanto often just uses the object directly.

Antaŭ ol means before when it introduces a whole clause.

Here:

• antaŭ ol ŝi eniras = before she enters

A useful way to remember it:

• antaŭ = before
• ol introduces the following clause after words like antaŭ

So if a verb follows, Esperanto normally uses antaŭ ol.

Because antaŭ by itself is often used before a noun or noun phrase, but before a full clause with a verb, Esperanto commonly uses antaŭ ol.

Compare:

• antaŭ la domo = in front of the house
• antaŭ la vespermanĝo = before dinner
• antaŭ ol ŝi eniras = before she enters

So ol helps show that what follows is a clause, not just a noun.

Because infano means child and is gender-neutral. The noun itself does not tell you whether the child is male or female.

The pronoun ŝi tells you that the child is female in this sentence.

So:

• infano = child (gender-neutral)
• ŝi = she

If the child were male, you would use li. If the gender were unknown or not important, the speaker might avoid repeating a pronoun or use another wording.

In this sentence, yes, that is the natural interpretation.

La infano frapas la pordon antaŭ ol ŝi eniras.

The most likely meaning is:

• The child knocks on the door before she enters.

Grammatically, pronouns usually refer back to the most sensible earlier noun. Since la infano is the person who could enter, ŝi is understood as referring to the child.

Yes, eniri is a normal Esperanto verb meaning to enter or to go in.

So:

• ŝi eniras = she enters / she goes in

Esperanto often builds verbs this way with prefixes:

• iri = to go
• en = in, into
• eniri = to enter

You may sometimes see expressions with separate words in other contexts, but eniri is the standard simple verb for enter.

Because here eniras is being used in the sense goes in or enters, without stating what she enters.

The sentence already gives the context: she knocks on the door before entering. So Esperanto does not need to repeat something like the house or the room.

In context, ŝi eniras simply means she enters / goes in.

Because the sentence is presented in the present tense as a general statement or as part of narration.

• frapas = knocks
• eniras = enters

Esperanto uses tense quite directly. If the whole situation is in the present, both verbs stay in the present.

If you wanted the past, you would change both:

• La infano frapis la pordon antaŭ ol ŝi eniris.
• The child knocked on the door before she entered.

The basic order is:

• La infano = subject
• frapas = verb
• la pordon = object
• antaŭ ol ŝi eniras = time clause

So the structure is:

Subject + verb + object + subordinate clause

This is a very normal Esperanto sentence pattern.

Yes. La is the definite article, like English the.

So:

• la infano = the child
• la pordon = the door

Unlike English, Esperanto has only one definite article: la. It does not change for gender, number, or case, although the noun may change, as in pordo → pordon.

Ŝi is pronounced roughly like shee in English.

A quick breakdown:

• ŝ sounds like English sh
• i sounds like ee

So ŝi = shee

This is one of the very regular features of Esperanto spelling: each letter has a consistent sound.

Literally, frapi can mean to strike or hit, so that idea is possible from the raw words. But in this context, with la pordon, the natural meaning is knocks on the door.

So a learner should understand:

• literal sense: hits/strikes the door
• natural English translation here: knocks on the door

Context usually makes the intended meaning clear.