Li metas la objekton sur la tablon.

The -n marks the direct object in Esperanto: the thing directly affected by the verb.

• Li metas = He puts
• la objekton = the object (the thing being put)

So objekton gets -n because it is what he is putting.

Not in the same way. In sur la tablon, the -n shows direction toward a place, not the main direct object.

This is a very important Esperanto pattern:

• sur la tablo = on the table (location, no movement)
• sur la tablon = onto the table (movement toward that place)

So in Li metas la objekton sur la tablon, the sentence shows movement onto the table, which is why tablon also has -n.

The difference is:

• sur la tablo = the object is on the table
• sur la tablon = the object moves onto the table

Compare:

• La libro estas sur la tablo. = The book is on the table.
• Li metas la libron sur la tablon. = He puts the book onto the table.

English often uses a different preposition such as on vs onto, but Esperanto often uses the same preposition plus the -n ending to show direction.

Because -as is the present tense ending in Esperanto.

• metas = puts / is putting
• metis = put / was putting
• metos = will put

So Li metas la objekton sur la tablon means He puts the object onto the table or He is putting the object onto the table, depending on context.

Yes. Esperanto does not normally have a separate verb form specifically for the English progressive (is putting).

So:

• Li metas... can mean He puts... or He is putting...

Context tells you which is meant. This is very normal in Esperanto.

Because both nouns are definite in this sentence:

• la objekton = the object
• la tablon = the table

Esperanto uses la for the, and it does not change for case or number. The -n goes on the noun, not on la.

So:

• la tablo
• la tablon
• la objekto
• la objekton

Also, Esperanto has no indefinite article. So there is no separate word for a/an.

Not necessarily wrong, but it means something different.

Without la, it sounds more like:

• He puts an object onto a table
• or He puts object(s) onto table(s) in a more general or less specific sense

With la, the speaker means a specific object and a specific table already known from context.

So:

• Li metas la objekton sur la tablon. = a specific object, a specific table
• Li metas objekton sur tablon. = less specific

Yes, Esperanto word order is fairly flexible because endings show grammatical roles.

The most neutral order is:

• subject + verb + object + phrase of place/direction

So this sentence is very natural.

Because objekton has -n, you could change the order and still understand it, for example:

• La objekton li metas sur la tablon.

This gives extra emphasis to the object.

But for learners, the basic order Li metas la objekton sur la tablon is the safest and most natural choice.

Yes, meti usually means to put, to place, or to set something somewhere.

Examples:

• Mi metas la libron sur la tablon. = I put the book on the table.
• Ŝi metis la ŝlosilojn en la sakon. = She put the keys in the bag.

It is a very common verb for placing something in a position or location.

Because sur means on or on top of, while en means in or inside.

So:

• sur la tablon = onto the table
• en la skatolon = into the box

A table has a surface, so sur is the natural choice.

Because Esperanto uses different pronouns:

• li = he
• ŝi = she
• ĝi = it
• ili = they

So Li metas... clearly means He puts...

Esperanto pronunciation is very regular. Roughly:

• objekton ≈ ob-YEK-ton
• tablon ≈ TA-blon
• metas ≈ ME-tas

A few helpful points:

• Stress is always on the second-to-last syllable
• Each letter is pronounced consistently
• j sounds like English y

So:

• o-BJEK-ton would be wrong if it moves the stress
• The correct stress is ob-YEK-ton

Yes. In Esperanto, -o marks a noun.

So:

• objekto = object
• tablo = table

Then other endings are added as needed:

• objekto = object
• objekton = object (direct object)
• tablo = table
• tablon = table (toward/onto the table, or direct object in other sentences)

This system is one of the most regular parts of Esperanto grammar.