Vimos un lobo cerca del río.

Vimos is the preterite form of ver (to see) for we.

So vimos = we saw.

The preterite is used for a completed action in the past. In this sentence, it means the seeing happened as a finished event: We saw a wolf near the river.

Vimos and veíamos both relate to seeing, but they are different past tenses.

• vimos = we saw → a completed event
• veíamos = we were seeing / we used to see → ongoing, repeated, or background action

So:

• Vimos un lobo cerca del río = We saw a wolf near the river
  (one completed sighting)

• Veíamos lobos cerca del río = We used to see wolves near the river or We were seeing wolves near the river
  (habitual or ongoing)

Spanish often leaves out subject pronouns because the verb ending already shows who the subject is.

• vimos already tells you the subject is we
• so (nosotros) vimos is usually just vimos

You can include nosotros for emphasis or contrast, but it is not necessary:

• Nosotros vimos un lobo = We saw a wolf
• Vimos un lobo = same basic meaning, and this is more natural in most contexts

Un lobo means a wolf — an unspecified wolf.

You use un when you are introducing something not already known or identified.

• Vimos un lobo = we saw a wolf
• Vimos el lobo = we saw the wolf
  (a specific wolf, already known from context)

So in this sentence, un lobo suggests it was just some wolf, not one already identified.

Spanish uses the personal a before a specific human direct object, and sometimes with personified animals or very specific animals.

Here, un lobo is just a general animal, not a person and not presented as a specific named creature, so no a is used:

• Vimos un lobo = correct

Compare:

• Vimos a María = We saw María
• Vimos a nuestro perro = possible, especially if the dog is seen as a familiar individual
• Vimos un lobo = no a

Because de + el contracts to del.

So:

• de el río → del río

This is mandatory in standard Spanish, except when el is part of a proper name:

• cerca del río = near the river
• vengo de El Escorial = from El Escorial
  (no contraction because El Escorial is a name)

Cerca normally works with de to mean near:

• cerca de = near

So:

• cerca del río = near the river

This is just the standard pattern in Spanish. You usually do not say cerca a in standard usage for this meaning.

Examples:

• cerca de casa = near home
• cerca de Madrid = near Madrid
• cerca del río = near the river

The accent mark shows that río is pronounced in two syllables:

• rí-o

Without the accent, it might be read as one syllable group. The accent helps show that the i and o are pronounced separately.

So río sounds roughly like REE-oh.

In standard Peninsular Spanish, a rough guide is:

VEE-mos oon LO-bo THER-ka del REE-o

A few key points:

• vimos = VEE-mos
• lobo = LO-bo
• cerca in Spain usually has the c before e pronounced like the th in thin
• río = REE-o, two syllables

So cerca is roughly THER-ka in much of Spain.

The order is very natural and common in Spanish:

• Vimos = verb
• un lobo = direct object
• cerca del río = place/location phrase

So the structure is basically:

[verb] + [object] + [location]

Because the subject we is omitted, the sentence starts directly with the verb.

You could change the order for emphasis, for example:

• Cerca del río vimos un lobo

That is still correct, but the original sentence is the most neutral wording.

Yes, depending on context, cerca del río can overlap with English expressions like near the river or sometimes by the river.

Its core meaning is close to the river, not necessarily right next to it.

If you want something more specifically like right by / next to, Spanish might use:

• junto al río = next to the river / right by the river
• al lado del río = beside the river

But cerca del río is a very normal and natural way to say near the river.