En marto kaj aprilo la rivero ofte ŝajnas pli granda, ĉar multe da pluvo falas.

In Esperanto, names of months and days are normally not capitalized unless they begin a sentence. So:

• marto = March
• aprilo = April

This is different from English, where March and April are capitalized.

Here en means in:

• en marto = in March
• en aprilo = in April

So En marto kaj aprilo means In March and April.

This is the normal way to talk about months in Esperanto.

Because they are objects of the preposition en, and prepositions normally do not take the accusative -n unless there is a special reason, such as motion toward something.

Here there is no movement, just a time expression:

• en marto = in March
• en aprilo = in April

So no -n is needed.

La means the. So la rivero means the river.

Esperanto uses la when the speaker means a specific river that is known from the context. That could be:

• a river already mentioned
• the local river everyone knows about
• a particular river being discussed in a text

If you said just rivero, it would sound more indefinite, more like a river or river as a general idea.

Ofte means often, and it is an adverb. In Esperanto, adverbs often go before the verb they modify:

• ofte ŝajnas = often seems

This is very natural word order. Esperanto word order is fairly flexible, so other placements can be possible, but ofte ŝajnas is the most straightforward choice here.

Ŝajnas means seems. The river is the subject, and pli granda describes how it seems.

So the structure is:

• la rivero = the river
• ŝajnas = seems
• pli granda = bigger / larger

Literally: the river often seems bigger

This is similar to English seems bigger. Esperanto does not need an extra word like to be here.

Because pli granda is a predicate adjective describing the subject la rivero.

With verbs like esti (to be), ŝajni (to seem), and similar verbs, the adjective stays in its basic adjective form:

• la rivero estas granda = the river is big
• la rivero ŝajnas granda = the river seems big

It is not a direct object, so it does not take -n.

The comparison is understood from the context. It means something like:

• bigger than usual
• bigger than in other months
• bigger than it normally looks

Esperanto, like English, does not always need to state the second half of a comparison if it is obvious.

If you wanted to say it explicitly, you could add ol:

• pli granda ol kutime = bigger than usual

Multe da pluvo means a lot of rain or much rain.

Here:

• multe = much / a lot
• da = of, in the special sense used after quantity words
• pluvo = rain

In Esperanto, after words showing quantity, you often use da:

• multe da akvo = a lot of water
• iom da tempo = a bit of time
• sufiĉe da mono = enough money

So da links the quantity word to the thing being measured.

Because pluvo here is a mass noun, like rain in English. It is being treated as an uncountable substance, not as separate individual rains.

So:

• multe da pluvo = a lot of rain

The plural pluvoj would suggest separate rain events or kinds of rain, which is not what this sentence is talking about.

Because in Esperanto, rain falls, just as in English:

• pluvo falas = rain falls

This is a normal and idiomatic way to say it. The sentence is describing the cause of the river seeming larger: a lot of rain falls.

The present tense is often used for general truths, habits, or repeated seasonal patterns.

So this sentence is not necessarily about just one specific March and April. It can mean something like:

• In March and April, the river often seems larger, because a lot of rain falls.

That is a general observation, so the present tense is natural.

Ĉar means because, and it introduces a whole clause:

• ĉar multe da pluvo falas = because a lot of rain falls

This is different from pro, which means because of and is followed by a noun phrase, not a full clause:

• pro la pluvo = because of the rain

So in this sentence, ĉar is the correct choice because what follows is a full statement with a verb: pluvo falas.

Not necessarily. Ŝajnas only tells you about appearance or impression:

• ŝajnas pli granda = seems bigger

That can mean:

• it only looks bigger, or
• it actually is bigger, but the speaker is describing how it appears

So ŝajnas is a little more cautious than directly saying estas pli granda (is bigger).