У меня сломалась точилка, поэтому я не могу заточить карандаш.

In Russian, у меня literally means by me / at my place, but very often it is used where English would say I have.

So:

• У меня сломалась точилка = literally My sharpener broke / At my place, the sharpener broke
• Russian does not usually say Я имею... for ordinary possession the way English says I have

This у + genitive structure is extremely common:

• У меня есть книга = I have a book
• У него машина = He has a car

Here, у меня sets the context: as for me / my sharpener.

Because the verb in the past tense agrees with the subject in gender and number.

The subject here is точилка (sharpener), and точилка is:

• feminine
• singular

So the past tense form must also be feminine singular:

• сломался = masculine
• сломалась = feminine
• сломалось = neuter
• сломались = plural

Since точилка is feminine, Russian uses сломалась.

Сломалась means broke or got broken / stopped working.

It comes from сломаться, which is a reflexive/intransitive verb meaning:

• to break
• to become broken
• to stop functioning

Compare:

• Я сломал точилку = I broke the sharpener
  Here someone caused the breakage.
• Точилка сломалась = The sharpener broke
  Here the sharpener itself is presented as becoming broken.

So in this sentence, сломалась means the sharpener is now broken and unusable.

Because у меня is not the grammatical subject. It is a phrase meaning something like as for me / belonging to me / in my possession.

The actual subject is точилка, because that is the thing that сломалась.

A good way to see this is by checking verb agreement:

• сломалась is feminine singular
• it agrees with точилка, not with меня

So the structure is roughly:

• У меня = my / in my possession
• сломалась точилка = the sharpener broke

Поэтому means therefore / so / that’s why.

It links the two ideas:

• У меня сломалась точилка
• поэтому я не могу заточить карандаш

So the meaning is: My sharpener broke, so I can’t sharpen the pencil.

It often appears near the beginning of the second clause, as it does here. That is very natural.

You may also see similar connectors such as:

• поэтому = therefore / so
• потому что = because

Important difference:

• ..., поэтому ... = ..., so ...
• ... потому что ... = ... because ...

For example:

• Точилка сломалась, поэтому я не могу заточить карандаш.
• Я не могу заточить карандаш, потому что точилка сломалась.

Both are natural, but they organize the logic differently.

Не могу + infinitive means cannot / am not able to do something.

So:

• я не могу заточить карандаш = I can’t sharpen the pencil

This focuses on inability, not simply on the fact that the action is not happening.

Compare:

• Я не точу карандаш = I’m not sharpening the pencil
  This could mean you are simply not doing it.
• Я не могу заточить карандаш = I can’t sharpen the pencil
  This means you are unable to do it.

So не могу is important because the broken sharpener makes the action impossible.

This is about aspect, one of the most important parts of Russian verbs.

• точить = imperfective
• заточить = perfective

In this sentence, заточить is used because the meaning is to sharpen the pencil successfully / to a finished result.

So:

• заточить карандаш = to sharpen a pencil completely
• точить карандаш = to be sharpening a pencil / to sharpen pencils in general / repeatedly

After мочь (can / be able to), Russian often chooses the aspect based on meaning:

• не могу заточить карандаш = I can’t get the pencil sharpened / I can’t sharpen it successfully
• не могу точить карандаш would sound more like I’m unable to do the activity of sharpening in a more general or ongoing sense

Here the perfective заточить is the most natural choice because the goal is a completed result.

In заточить, the prefix helps form the perfective verb from точить.

Very often, prefixes in Russian add both:

• a change in meaning
• or a sense of completion/result

Here, the main practical point for learners is:

• точить = imperfective, process
• заточить = perfective, completed sharpening

You do not always need to translate the prefix separately. In many cases, it is best to learn the pair together as:

• точить / заточить = to sharpen

with the difference being aspect rather than a completely different English meaning.

Because карандаш is the direct object of заточить.

The verb заточить takes the accusative case:

• заточить что? — карандаш

Now, карандаш is masculine and inanimate. For masculine inanimate nouns, the accusative singular is the same as the nominative singular.

So:

• nominative: карандаш
• accusative: карандаш

That is why the form does not change.

Compare with a feminine noun:

• заточить ручку
• nominative: ручка
• accusative: ручку

Yes, here точилка means pencil sharpener.

It comes from the verb точить (to sharpen), so точилка is literally a device or tool used for sharpening.

Depending on context, it could theoretically mean some kind of sharpening tool, but in everyday speech it normally means a pencil sharpener.

So in this sentence:

• точилка = sharpener
• most naturally: pencil sharpener

Russian has no articles.

English distinguishes between:

• a sharpener
• the sharpener

Russian usually does not mark that directly with a separate word. The exact meaning depends on context.

So:

• точилка can mean a sharpener or the sharpener
• карандаш can mean a pencil or the pencil

In this sentence, English will usually translate them as:

• My sharpener broke, so I can’t sharpen the pencil
• or ...a pencil, depending on the situation

Context tells you which one is meant.

Yes. Russian word order is flexible, although some orders sound more neutral than others.

The given sentence is very natural:

• У меня сломалась точилка, поэтому я не могу заточить карандаш.

You could also say:

• Точилка у меня сломалась, поэтому я не могу заточить карандаш.
• Я не могу заточить карандаш, потому что у меня сломалась точилка.

These versions shift emphasis slightly:

• starting with У меня emphasizes my situation
• starting with Точилка emphasizes the sharpener
• using потому что instead of поэтому changes the logical structure from so to because

For learners, the original version is a very good neutral model.

A helpful stress guide is:

• У меня́ слома́лась точи́лка, поэтому́ я не могу́ заточи́ть каранда́ш.

Main stressed syllables:

• меня́
• слома́лась
• точи́лка
• поэтому́
• могу́
• заточи́ть
• каранда́ш

A rough pronunciation guide:

• У меня́ = oo mee-NYA
• слома́лась = sla-MA-las’
• точи́лка = ta-CHEEL-ka
• поэтому́ = pa-e-ta-MOO
• я не могу́ = ya nee ma-GOO
• заточи́ть = za-ta-CHEET’
• каранда́ш = ka-ran-DASH

Stress is very important in Russian, because it is not always predictable.

Sometimes yes, but сломалась is the more standard and straightforward choice here.

Both can mean that something broke, but there can be slight differences in tone or usage depending on context and region.

For a learner, the safest choice is:

• сломаться = to break / become broken

So:

• У меня сломалась точилка is fully natural and standard

You may hear поломалась in conversation, but сломалась is the better core verb to learn first.