Mijn been is moe na de lange wandeling, maar mijn arm voelt nog sterk.

In Dutch, a possessive determiner like mijn replaces the article. So you say mijn been, not het mijn been, and mijn arm, not de mijn arm.

This works just like:

• mijn fiets = my bike
• haar huis = her house
• onze kinderen = our children

So once you use mijn, you do not add de or het.

They are:

• het been = the leg
• de arm = the arm
• de wandeling = the walk

This is useful to memorize, because the article disappears after mijn, but the noun still keeps its gender behind the scenes.

Yes, been normally means leg in modern Dutch.

The usual word for bone is bot.

So:

• been = leg
• bot = bone

Plural forms:

• been → benen
• bot → botten

Because they are predicative adjectives: they come after a verb like zijn or voelen, not directly before a noun.

In Dutch, predicative adjectives usually stay in their basic form:

• Het been is moe.
• De arm voelt sterk.
• De man is aardig.

So you do not say moee or sterke here.

Because here the adjective comes before the noun. That is called attributive use.

When an adjective comes before a noun in Dutch, it usually takes -e:

• de lange wandeling
• de sterke arm
• het mooie huis

So:

• sterk after the verb: mijn arm voelt sterk
• sterke before a noun: de sterke arm

Both are possible, but they give slightly different shades of meaning.

• is moe states a condition directly: my leg is tired
• voelt sterk emphasizes how it feels: my arm feels strong

So the sentence contrasts:

• the leg’s state: moe
• the arm’s felt condition: nog sterk

You could also say:

• Mijn arm is nog sterk.

That is also correct, but voelt nog sterk sounds a bit more physical and experiential.

Because with a body part as the subject, Dutch normally just uses voelen without the reflexive zich.

• Mijn arm voelt sterk. = My arm feels strong.

But when a person is the subject, Dutch often uses zich:

• Ik voel me sterk. = I feel strong.
• Hij voelt zich moe. = He feels tired.

So:

• Ik voel me sterk
• Mijn arm voelt sterk

That difference is very common in Dutch.

Here nog means still.

So:

• mijn arm voelt nog sterk = my arm still feels strong

It suggests continuation: despite the long walk, the arm remains strong.

Nog can have other meanings in other contexts, such as yet, another, or more, but in this sentence still is the best match.

Because the subjects are singular:

• mijn been = singular
• mijn arm = singular

So the verbs are singular too:

• been is
• arm voelt

If they were plural, you would say:

• Mijn benen zijn moe.
• Mijn armen voelen nog sterk.

Maar means but and is a coordinating conjunction. It joins two main clauses.

That means each part keeps normal main-clause word order:

• Mijn been is moe na de lange wandeling
• maar mijn arm voelt nog sterk

So after maar, you do not send the verb to the end. This is different from subordinating conjunctions like omdat.

Compare:

• ..., maar mijn arm voelt nog sterk.
• ..., omdat mijn arm nog sterk voelt. (less natural wording here, but verb-final structure after *omdat is the point)*

Yes. It is a prepositional phrase, so it can move.

For example:

• Na de lange wandeling is mijn been moe, maar mijn arm voelt nog sterk.

When you move something to the beginning of a Dutch main clause, the finite verb usually comes next. That is the usual V2 pattern:

• Na de lange wandeling
  • is
    • mijn been
      • moe

So the original sentence and the moved version are both correct.

You would use the plural nouns and plural verbs:

• Mijn benen zijn moe na de lange wandeling, maar mijn armen voelen nog sterk.

Changes:

• been → benen
• arm → armen
• is → zijn
• voelt → voelen

So Dutch agreement works much like English here: plural subject, plural verb.