Mi metas grason sur la ĉenon.

Because metas is a conjugated verb, while meti is the infinitive.

• meti = to put / to place
• metas = put / am putting / do put

In Esperanto, present-tense verbs always end in -as:

• mi metas = I put / I am putting
• vi metas = you put
• li metas = he puts

So Mi metas... is a complete sentence, but Mi meti... would be ungrammatical.

Meti means to put, to place, or to set something somewhere.

So Mi metas grason sur la ĉenon means that the speaker is actively putting grease onto the chain.

It is a very common verb for physically placing something:

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

Because it is the direct object of the verb.

In Esperanto, the direct object usually takes -n. The direct object is the thing directly affected by the action.

Here:

• Mi = the subject, the person doing the action
• metas = the action
• grason = the thing being put

So:

• graso = grease
• grason = grease, as the direct object

This is one of the most important uses of -n in Esperanto.

Because after a preposition, -n can show direction toward a place.

Compare:

• sur la ĉeno = on the chain (location)
• sur la ĉenon = onto the chain (movement/direction)

In this sentence, the grease is being put onto the chain, so Esperanto uses sur la ĉenon.

This is a very common pattern:

• La kato estas sur la tablo. = The cat is on the table.
• La kato saltas sur la tablon. = The cat jumps onto the table.

So ĉenon is not the direct object here; it has -n because it shows movement toward the chain.

It can mean either, depending on whether there is an -n ending.

• sur + no -n = on (location)
• sur + -n = onto (direction)

So:

• sur la ĉeno = on the chain
• sur la ĉenon = onto the chain

English often uses two different words, but Esperanto often uses the same preposition and lets the -n show the difference.

Because la means the, and Esperanto has no separate word for a/an.

So:

• la ĉenon = the chain
• grason = grease / some grease

In many contexts, an unmarked noun can be indefinite or general. So grason here naturally means something like grease or some grease.

Esperanto only has a definite article, la. There is no indefinite article equivalent to a or an.

Yes. All present-tense verbs end in -as, regardless of the subject.

Examples:

• mi metas = I put / am putting
• vi metas = you put
• li metas = he puts
• ni metas = we put

Esperanto verbs do not change depending on the person, unlike English.

For comparison:

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

ĉ is pronounced like ch in church.

So ĉeno sounds roughly like CHEH-no.

Breaking it down:

• ĉe = like che in check, but with a clearer pure vowel
• no = no
• -n at the end of ĉenon is pronounced normally

A few useful pronunciation points:

• ĉ = ch as in chocolate
• e = like e in bet
• o = a pure o sound
• stress in Esperanto usually falls on the second-to-last syllable

So ĉe-NON is the stressed form of ĉenon.

The base form is ĉeno, meaning chain.

Then:

• ĉeno = chain
• la ĉeno = the chain
• ĉenon = chain, with -n for direction or direct-object marking
• la ĉenon = the chain, with -n

In this sentence, the -n comes from the directional use after sur.

Yes, Esperanto word order is fairly flexible, mainly because the endings show the grammar.

The most neutral order is:

• Mi metas grason sur la ĉenon.

But other orders are possible in the right context, for emphasis, for example:

• Sur la ĉenon mi metas grason.
• Grason mi metas sur la ĉenon.

That said, the standard, beginner-friendly order is the one in your sentence.

It can mean both, depending on context.

• In everyday or physical contexts, graso can mean fat or grease.
• In a mechanical sentence like this one, it naturally means grease.

So in Mi metas grason sur la ĉenon, the meaning is clearly mechanical lubricant, not body fat.

If needed, context or extra words can make it more precise, but graso works well here.