Podemos remendar el descosido.

Podemos is the present indicative of poder for nosotros:

• yo puedo
• tú puedes
• él/ella puede
• nosotros podemos

So here it means we can or we are able to.

Spanish often drops subject pronouns when they are not needed, because the verb ending already shows who the subject is. That is why nosotros is omitted. You could say Nosotros podemos remendar el descosido, but it is usually unnecessary unless you want emphasis or contrast.

After poder, Spanish normally uses a second verb in the infinitive:

• Puedo ir
• Puedes hacerlo
• Podemos remendar

This works like English can + base verb:

• We can mend

So podemos remendar is the normal structure. There is no preposition between them.

Not exactly.

Remendar means to mend, patch, or repair, especially fabric or clothing. It focuses on fixing damage.

Coser means to sew in a more general sense. You can coser something new, or you can coser something back together.

A useful comparison:

• coser = to sew
• remendar = to mend/patch
• arreglar = to fix/repair in a general sense
• zurcir = to darn, especially small holes in fabric or socks

So remendar is a good choice when talking about repairing clothing or cloth.

Here descosido refers to the part that has come unstitched, such as:

• an undone seam
• a split seam
• an unsewn or opened section of stitching

It comes from the verb descoser, which means to unsew or to come unstitched.

So the idea is not just any damage in fabric, but specifically something whose stitching has come undone.

In origin, descosido is related to a past participle/adjectival form of descoser.

But in this sentence, it is being used like a noun: it means the unstitched part or the undone seam.

Spanish often does this with adjectives or participle-like forms:

• el roto = the tear / ripped part
• el descosido = the unstitched part
• lo roto = what is torn / the torn part in a more abstract sense

So in this sentence, treat el descosido as a noun phrase.

Because el descosido refers to a specific, countable thing: a particular unstitched area or seam.

By contrast, lo descosido is more abstract or general, meaning something like:

• what is unstitched
• the unstitched part, in a less concrete way

In everyday Spanish, if you are talking about a particular place on a garment, el descosido is the more natural choice.

El suggests that the speaker and listener are thinking of a specific descosido already known from the context.

So:

• el descosido = the undone seam / the unstitched part
• un descosido = an undone seam / some unstitched part

If you are looking at a particular jacket or shirt and both people know which damaged spot is being discussed, el makes sense.

Because the expression is treated as a masculine noun phrase here.

The article agrees with the noun phrase actually being used:

• el descosido

If you used a different noun, the gender could change:

• la costura descosida = the seam that has come undone
• la parte descosida = the unstitched part

So the masculine article is not arbitrary; it matches the form being used in this sentence.

Yes. If the context already makes clear what you are talking about, lo can replace el descosido:

• Podemos remendarlo = We can mend it

This is very common in natural speech. The full version Podemos remendar el descosido is clearer when you want to name the object explicitly.

Yes, it is completely normal.

The neutral order here is:

• Podemos = conjugated verb
• remendar = infinitive
• el descosido = direct object

So:

• Podemos remendar el descosido

Spanish word order is flexible, but this is the most straightforward and standard version.

It is grammatical and understandable in Spain.

That said, in everyday speech, some speakers might more naturally say things like:

• Podemos coser el descosido
• Podemos arreglarlo
• Podemos coser la parte que se ha descosido
• Podemos arreglar la costura

Which version sounds most natural depends on the exact situation:

• If the stitching has come undone, coser or arreglar la costura is very natural.
• If the idea is general mending, remendar also works well.

So the sentence is fine, but in real conversation there are several common alternatives.