No puedo enfocar la pantalla.

In Spanish, no normally goes before the conjugated verb to make the sentence negative.

• No puedo = I can’t
• Puedo = I can

So:

• No puedo enfocar la pantalla. = I can’t focus the screen.

Putting no after puedo would not be normal here.

Because the subject is an understood I.

Poder = to be able to / can

Present tense:

• yo puedo = I can
• tú puedes = you can
• él/ella puede = he/she can
• nosotros podemos = we can
• vosotros podéis = you all can
• ellos pueden = they can

Spanish often leaves out the subject pronoun, so puedo already tells you the subject is yo.

• (Yo) no puedo enfocar la pantalla.

After poder, Spanish uses an infinitive.

So the structure is:

• poder + infinitive

Examples:

• Puedo leer. = I can read.
• No puedo dormir. = I can’t sleep.
• No puedo enfocar la pantalla. = I can’t focus the screen.

You do not say No puedo enfoco... because only the first verb is conjugated.

Enfocar literally means to focus or to bring into focus.

Depending on context, it can be used for:

• a camera
• your eyes/vision
• directing attention toward something

With la pantalla, it often suggests:

• not being able to get the screen visually into focus
• not being able to focus a camera on the screen

So the exact nuance depends on the situation.

Spanish often uses the definite article where English may or may not use one.

• la pantalla = the screen

In this sentence, the screen is treated as a specific thing the speaker is referring to.

So:

• No puedo enfocar la pantalla.

sounds natural and complete.

Yes. That is correct.

Spanish often drops subject pronouns because the verb ending already shows who the subject is:

• No puedo enfocar la pantalla.

If you add yo, it usually adds emphasis, contrast, or clarity:

• Yo no puedo enfocar la pantalla, pero ella sí.
  = I can’t focus the screen, but she can.

So both are correct, but the version without yo is more neutral and more common.

Yes.

Because la pantalla is a direct object, you can replace it with la:

• No puedo enfocar la pantalla.
• No la puedo enfocar.

Both are correct.

You can also attach the object pronoun to the infinitive:

• No puedo enfocarla.

So these three are all possible:

• No puedo enfocar la pantalla.
• No la puedo enfocar.
• No puedo enfocarla.

Not exactly.

Enfocar la pantalla usually means to focus the screen as a direct object — for example, visually or with a camera.

If you mean I can’t concentrate on the screen, Spanish would often use a different expression, such as:

• No puedo concentrarme en la pantalla.

So English focus can correspond to different Spanish verbs depending on whether you mean:

• visual focus → enfocar
• mental concentration → concentrarse

Because in this sentence, la pantalla is the direct object of enfocar.

• enfocar algo = to focus something

So:

• enfocar la pantalla = to focus the screen

If you use a different structure, you may get en:

• concentrarse en la pantalla = to concentrate on the screen
• enfocar la vista en la pantalla = to focus your gaze on the screen

But with enfocar + direct object, no en is needed.

Roughly: pan-TA-ya

A few points:

• stress is on ta: pan-TA-lla
• ll in most of Spain is pronounced much like an English y sound
• ñ does not appear here; it is just n

So pantalla sounds approximately like pan-TA-ya.

Mostly yes, but it has a spelling change in some forms to keep the hard c/k sound.

For example:

• enfoco
• enfocas
• enfoca

But in forms before e, it changes:

• enfoqué (not enfocé) = I focused

This is the same kind of spelling change seen in verbs like:

• buscar → busqué
• tocar → toqué

In your sentence, though, it appears as the plain infinitive:

• enfocar

Yes, it can sound natural in Spain, especially in a context involving:

• eyesight
• a camera
• trying to get an image clear

That said, the most natural sentence depends on the situation. For example:

• If you mean I can’t get the screen into focus visually, this works.
• If you mean I can’t concentrate on the screen, Spaniards would more likely say something like No puedo concentrarme en la pantalla.

So the sentence is grammatical and natural, but the exact best choice depends on what kind of focus you mean.