concentrate

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Yes, those are reasonably synonymous. We tend to pay attention to other activities (a TV show, a teacher, a ball game) and concentrate on our own (my lesson, my knitting), I think.
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Concentrate means to spend all your mental energy on doing something. It usually means to devote a long period of time to doing something.
Pay attention to is not as "heavy weight" as concentrate. It means to "direct one's attention to"
I paid attention to the teacher in class.
For years, he concentrated on perfecting his singing voice.

Hi, thank you both for your replies.

The dictionary says that "concentrate" means "to give all your attention to something and not think about anything else."

I think 'pay attetion to' has the same meaning as that. So sometimes I can't figure out their difference. For example:

I can’t concentrate with all that noise going on.

I can't pay attention with all that

See the difference:

Concentrate means to bring all efforts, faculties, activities, etc., to bear on one thing or activity (often fol. by on or upon): to concentrate on solving a problem.

"Pay attention to" means - be attentive to, direct your focus to, as in "Now pay attention to these instructions".

A teacher would say "pay attention to me", he would not say "concentra

Hi AlphecaStars,

Thank you very much for your reply. So, in the example

I can't concentrate on/pay attention to my work when I'm hungry.

Do concentrate and pay attention mean the same and interchangeable here?

Hi,
Could anyone please help me with my question above?
Thanks a lot.

Yes, in this example, they mean nearly the same. "Concentrate on" is more intense, and I would usually select this instead of "pay attention to".Another word I might use is "focus on" which is in between in intensity.