Ni adoptos la hundidon nur se ĝi estas sana.

Adoptos is the future tense of adopti = to adopt.

Esperanto verb endings are very regular:

• -as = present
• -is = past
• -os = future
• -us = conditional
• -u = command / jussive
• -i = infinitive

So:

• Ni adoptas = we adopt / we are adopting
• Ni adoptis = we adopted
• Ni adoptos = we will adopt

In this sentence, Ni adoptos means we will adopt.

The -n marks the direct object in Esperanto.

Here, the thing being adopted is the puppy, so la hundidon is the direct object of adoptos.

Breakdown:

• hundo = dog
• hundido = puppy
• hundidon = puppy as a direct object

So the -n is not part of the basic dictionary form; it is the accusative ending added because the puppy receives the action.

Hundido means puppy.

It is built from:

• hund- = dog
• -id- = offspring, young one
• -o = noun ending

So:

• hundo = dog
• hundido = young dog, puppy

This is a very common Esperanto word-building pattern. For example:

• kato = cat
• katido = kitten

La is the definite article, meaning the.

So la hundidon means the puppy, not just a puppy.

Esperanto has:

• la = the
• no separate word for a/an

Whether English uses a or no article is often understood from context. But when Esperanto uses la, it clearly means a specific one.

In this sentence, la hundidon suggests a particular puppy that both speaker and listener know about.

Se means if.

Nur se means only if.

That is an important difference:

• Ni adoptos la hundidon se ĝi estas sana
  = We will adopt the puppy if it is healthy.
  This gives a condition, but does not strongly exclude other possibilities.

• Ni adoptos la hundidon nur se ĝi estas sana
  = We will adopt the puppy only if it is healthy.
  This means being healthy is a required condition.

So nur adds the idea of restriction: only.

Ĝi is the pronoun usually used for things, animals, and babies when no sex is being specified.

Since hundido is an animal and the sentence does not say whether it is male or female, ĝi is the normal choice.

Common pronouns here would be:

• li = he
• ŝi = she
• ĝi = it

So ĝi estas sana means it is healthy.

Yes, if the sex of the puppy is known and relevant.

For example:

• Ni adoptos la hundidon nur se li estas sana = ...only if he is healthy
• Ni adoptos la hundidon nur se ŝi estas sana = ...only if she is healthy

But if the sex is unknown, unspecified, or unimportant, ĝi is the usual form.

Because sana is a predicate adjective, not a direct object.

In ĝi estas sana, the word sana describes the subject ĝi after the verb estas. Predicate adjectives in Esperanto normally do not take -n.

Compare:

• La hundido estas sana = The puppy is healthy
• Ni vidas la sanan hundidon = We see the healthy puppy

In the second sentence, sanan gets -n because it describes a direct object (hundidon), and adjectives agree with the nouns they modify.

But in ĝi estas sana, there is no direct object, so no -n.

Because the subject is singular: ĝi = it.

Adjectives in Esperanto agree with the noun or pronoun they describe in number and sometimes case.

Here:

• ĝi = singular
• so sana = singular

If the subject were plural, you would use sanaj:

• Ili estas sanaj = They are healthy

Esperanto word order is fairly flexible, but this sentence uses the most natural and straightforward order.

Standard order here is:

• Ni = subject
• adoptos = verb
• la hundidon = object
• nur se ĝi estas sana = condition

Because Esperanto marks the direct object with -n, some movement is possible. But for learners, the normal order is best.

For example, these are possible, though less neutral:

• Nur se ĝi estas sana, ni adoptos la hundidon.
• La hundidon ni adoptos nur se ĝi estas sana.

The original version is clear and natural.

No, Esperanto normally keeps the subject explicit.

English can sometimes say things like only if healthy in a shortened way. Esperanto can also shorten in some contexts, but the full sentence nur se ĝi estas sana is the clearest and most standard form here.

So using ĝi is completely normal and expected.

A close equivalent would be:

Ni ne adoptos la hundidon, se ĝi ne estas sana.

Literally: We will not adopt the puppy if it is not healthy.

You may also see other ways to express similar logic, but the original sentence with nur se is very direct and common for only if.

The dictionary forms are:

• ni = we
• adopti = to adopt
• la = the
• hundo = dog
• -id- = young one / offspring
• ĝi = it
• esti = to be
• sana = healthy
• se = if
• nur = only

From those, the sentence is built very regularly:

• adopti → adoptos
• hundo
  • -id-
    • -o → hundido
• hundido
  • -n → hundidon

That regularity is one of the biggest advantages of Esperanto.