En nia klaso ne ĉiu demando estas facila, sed kiam la instruistino bone klarigas la temon, ĝi fariĝas pli simpla.

En normally means in. So En nia klaso means in our class.

That can mean:

• physically in the classroom
• within our class group
• in the context of our class

Esperanto often uses en just like English in for this kind of setting.

Because the meaning is not every question is easy, not no question is easy.

• ne ĉiu demando = not every question / not all questions
• neniu demando = no question

So this sentence leaves room for some questions to be easy.

Because ĉiu means each or every, and in Esperanto it normally goes with a singular noun.

So:

• ĉiu demando = every question
• ĉiuj demandoj = all the questions

A native English speaker may expect plural because the overall idea is plural, but Esperanto treats ĉiu as referring to each item one by one.

Because facila describes ĉiu demando, which is singular.

In Esperanto, adjectives agree with the noun in:

• number
• accusative case

So here:

• demando = singular
• facila = singular

If the noun were plural, you would say facilaj.

Because facila is a predicate adjective after estas, not a direct object.

In ĉiu demando estas facila:

• ĉiu demando is the subject
• estas is the verb
• facila describes the subject

Predicate adjectives do not take -n just because they describe something. They only take -n if normal accusative rules require it.

Instruisto means teacher.
Instruistino means female teacher.

The ending part -in- marks female sex:

• patro = father
• patrino = mother
• instruisto = teacher
• instruistino = female teacher

So the sentence specifically tells you the teacher is a woman.

Because bone is an adverb, and it modifies the verb klarigas.

• bona = good, as an adjective
• bone = well, as an adverb

Here the meaning is that the teacher explains well, so you need the adverb:

• la instruistino bone klarigas = the teacher explains well

Using bona would be wrong here because bona has to describe a noun.

Because la temon is the direct object of klarigas.

The teacher is explaining the topic, so the topic receives the action. In Esperanto, direct objects usually take -n.

• la temo = the topic
• la temon = the topic, as direct object

So:

• la instruistino klarigas la temon = the teacher explains the topic

La is the definite article, like English the.

It is used when the speaker has a specific person or thing in mind:

• la instruistino = the teacher
• la temo / la temon = the topic

That suggests the class already knows which teacher and which topic are meant.

Because fariĝas means becomes, not just is.

• estas pli simpla = is simpler
• fariĝas pli simpla = becomes simpler

So the sentence shows a change: after the teacher explains well, something becomes simpler than before.

Because simpla describes the subject ĝi, so it must be an adjective.

• simpla = simple
• simple = simply

Here the meaning is it becomes simpler, so simpla is correct.

If you used simple, that would describe the manner of the action, something like becomes simply, which is not what is meant.

This is a very natural question, because the sentence is a bit ambiguous.

Ĝi could in principle refer to:

• la temo = the topic
• demando = the question

Many readers will probably understand it as the topic, because that is the nearest noun and it is the thing being explained. But since the first part talks about demando, some readers may hesitate.

If you want to make it fully clear, Esperanto often just repeats the noun:

• ... la temo fariĝas pli simpla
• ... la demando fariĝas pli simpla

So the original sentence is possible, but not maximally clear.

Because the sentence describes a general situation or usual truth, not one single completed event.

In Esperanto, the present tense -as is used for:

• what is happening now
• habitual actions
• general statements

So here it means something like:

• in our class, not every question is easy
• but when the teacher explains well, it becomes simpler

This is a general classroom observation.

Yes. Esperanto word order is fairly flexible, as long as the grammar stays clear.

For example:

• kiam la instruistino bone klarigas la temon
• kiam la instruistino klarigas bone la temon

Both are understandable, though bone klarigas is very natural.

Also, the kiam clause could be placed differently depending on emphasis. Esperanto often uses commas to separate such clauses, just as in this sentence.