Translation of "Concentrating" in Spanish

I'm concentrating.

Me estoy concentrando.

- I have difficulty concentrating.
- I'm having trouble concentrating.

- Me cuesta concentrarme.
- Tengo dificultad para concentrarme.

Or reading, concentrating.

o leer, la concentración.

I have difficulty concentrating.

- Me cuesta concentrarme.
- Tengo dificultad para concentrarme.

Tom isn't concentrating, is he?

Tom no está concentrándose, ¿verdad?

Tom has trouble concentrating on one thing.

Tom tiene problemas para concentrarse en una cosa.

Tom always seems to be concentrating on something.

Tom siempre parece estar concentrándose en algo.

- I'm incapable of focusing.
- I'm incapable of concentrating.

Soy incapaz de concentrarme.

- I'm having a hard time concentrating.
- I'm having trouble focusing.

Me cuesta concentrarme.