O penhasco fica junto ao percurso.

Penhasco is a masculine singular noun, so the definite article is o.

In Portuguese, articles are used more often than in English. So where English might say Cliff is next to the route only in a headline or note, normal Portuguese prefers O penhasco...

Compare:

• o penhasco = the cliff
• um penhasco = a cliff

Fica is the 3rd person singular present tense of the verb ficar.

It matches the subject o penhasco, which is singular.

A few related forms:

• eu fico = I stay / I am located
• tu ficas = you stay / are located
• ele/ela fica = he/she/it stays / is located
• eles/elas ficam = they stay / are located

Here, fica is being used in the sense of is located or lies.

In sentences about location, ficar very often means to be situated / to be located / to lie.

So O penhasco fica junto ao percurso sounds like:

• The cliff is located next to the route
• The cliff lies next to the route

Why not the others?

• ser is generally not used for normal physical location.
• estar can express location, but ficar is especially common when describing where something is on a map, in a landscape, or in relation to something else.

So fica is very natural here.

Junto a means next to, right by, or close to.

It usually suggests fairly close physical proximity, often closer or more direct than perto de.

So:

• junto ao percurso = next to the route
• perto do percurso = near the route

Both are possible, but junto a gives more of a sense of being immediately beside something.

Because ao is a contraction of:

• a
  • o = ao

The expression is junto a + o percurso, so it becomes:

• junto ao percurso

This is a very common feature of Portuguese.

Other examples:

• a + a = à
• a + os = aos
• a + as = às

For example:

• junto à estrada = next to the road
• junto aos edifícios = next to the buildings

Percurso is a masculine noun meaning something like route, course, or pathway depending on context.

It often refers to:

• a route someone follows
• a planned or marked course
• a stretch of path or trail

Compared with some similar words:

• caminho = path, way, road
• trilho = trail, track
• percurso = route/course, often a bit more neutral or formal

So percurso works well if you are talking about a route, trail, or marked path.

Yes, you may hear both junto ao percurso and junto do percurso.

In practice:

• junto ao percurso is very standard
• junto do percurso is also used

For a learner, the important thing is to recognize that both can express next to the route. The sentence you were given uses junto a, which triggers the contraction ao.

Yes, but the nuance is a little different.

• junto ao percurso = right next to the route / immediately beside it
• perto do percurso = near the route

So perto de is a bit broader and less exact. If something is close but not necessarily directly beside the route, perto de may fit better.

Not strictly as a grammar rule, but in this kind of sentence it often sounds like a stable fact about where something is situated.

With landmarks, buildings, and geographical features, ficar commonly gives the idea of being located rather than emphasizing a temporary state.

So here it sounds natural because a cliff is a fixed feature in the landscape.

A useful approximation is:

penhasco → pe-NYASH-koo

A few sound notes:

• nh sounds like ny in canyon
• s in -hasco sounds like sh here
• the final o in European Portuguese is often reduced, sounding closer to u

So in European Portuguese, the word is often heard more like p'NYASH-ku than a fully open syllable-by-syllable pronunciation.

A rough learner-friendly approximation is:

O penhasco fica junto ao percurso
→ u p-nyASH-ku FEE-kə ZHOON-tu aw pər-KOOR-su

A few helpful points:

• O often sounds like u
• j in junto sounds like the s in measure
• ao sounds roughly like ow in now
• unstressed vowels are often reduced in European Portuguese

The real European Portuguese pronunciation is more compressed than the spelling suggests, so listening to native audio is especially useful here.