Mi madre guarda leche en el cuenco, ya que la botella no cabe en la nevera.

Because mi without an accent is the possessive adjective meaning my.

• mi madre = my mother
• mí with an accent means me after a preposition, as in para mí = for me

So mi madre is correct here.

No. Mi stays the same for both masculine and feminine singular nouns.

• mi madre
• mi padre
• mi casa
• mi libro

It only changes for number:

• mi madre
• mis padres

So mi does not become different just because madre is feminine.

Because leche is being used as a mass noun in a general, non-specific way. In Spanish, mass nouns often appear without an article after many verbs.

So:

• guarda leche = she stores milk
• bebe agua = he drinks water
• compra pan = she buys bread

If you were talking about a specific milk already known in context, you might use la:

• guarda la leche = she stores the milk

Both are possible, but the version without the article is very natural.

Guardar can mean several related things, including:

• to keep
• to store
• to put away
• sometimes to save

In this sentence, it means something like stores or keeps. The idea is not just placing the milk somewhere once, but keeping it there because of the space problem.

A learner might expect pone (puts), but guardar sounds more like storing/keeping something in a place.

Because en is used for location or position inside/on a place or container.

• en el cuenco = in the bowl
• en la nevera = in the fridge

A usually expresses movement toward a destination, and al means a + el. Here the focus is where the milk is kept, not movement toward the bowl.

So en el cuenco is the natural choice.

Cuenco usually means bowl, especially a bowl-like container. In Spain, it is a normal everyday word.

It suggests a container more than a cup or glass. Depending on context, English might translate it as:

• bowl
• sometimes dish

It is masculine: el cuenco.

Ya que means since, as, or because.

In this sentence, it introduces the reason:

• ya que la botella no cabe en la nevera = since/because the bottle doesn’t fit in the fridge

Compared with porque:

• porque is the most neutral and common word for because
• ya que often sounds a bit more explanatory, like giving background or a reason the speaker assumes makes sense in context

So both could work, but ya que feels slightly more like given that / since.

Because the clause introduced by ya que is being added as an explanation of the first clause.

Spanish often uses a comma before explanatory connectors like this:

• Mi madre guarda leche en el cuenco, ya que...

That punctuation helps separate the main statement from the reason. In practice, this is very natural and standard here.

It comes from the verb caber, which means to fit.

Present tense:

• quepo
• cabes
• cabe
• cabemos
• cabéis
• caben

So:

• la botella no cabe = the bottle doesn’t fit

Notice that the yo form is irregular (quepo), but cabe is the normal third-person singular form.

Both can sometimes be translated as to fit, but they are not exactly the same.

• caber focuses on whether there is enough space
• entrar often focuses more on going in or being able to go in

So:

• La botella no cabe en la nevera = the bottle doesn’t fit in the fridge
• La botella no entra en la nevera = the bottle doesn’t go into the fridge / won’t go in

In many contexts both are possible, but no cabe is especially good when the problem is lack of space.

Because nevera is a feminine noun:

• la nevera
• en la nevera

The preposition en means in or inside here. So en la nevera simply means in the fridge.

It is very common in Spain, yes. A few notes:

• nevera = very common everyday word in Spain
• frigorífico = also used in Spain, often a bit more formal or technical
• in other Spanish-speaking countries, people may also say refrigerador, heladera, and other regional terms

So for Spain Spanish, nevera is an excellent word to learn.

Because Spanish usually leaves out subject pronouns when the verb already makes the subject clear.

• Mi madre guarda... already tells you who is doing the action
• adding ella would usually be unnecessary unless you want emphasis or contrast

For example:

• Ella guarda leche en el cuenco, no mi padre = She stores milk in the bowl, not my father

But in a normal sentence, omitting the pronoun is more natural.

It can be either, depending on context. Spanish present tense often covers both:

• something happening now
• a habitual or regular action

So Mi madre guarda leche en el cuenco... could mean:

• she is doing that now, or
• this is what she normally does

Without more context, both readings are possible.

Yes. You could also say:

Ya que la botella no cabe en la nevera, mi madre guarda leche en el cuenco.

That is grammatically correct. The meaning stays basically the same, but the focus changes slightly:

• original order: statement first, then explanation
• changed order: reason first, then result/action

Both are natural, though the original sentence sounds very straightforward and common.