The words concentrate and focus have almost the same meaning in English. However, contrary to what many learners think, they are not the same in the passive form. In this post, I will explain the difference.
Concentrate / focus
In English, you can concentrate or focus (on something). As I mentioned above, there is very little difference in meaning:
I need to concentrate on my work. Please turn the music off.
I need to focus on my work. Please turn the music off.
Concentrated / focussed (American English: focused)
In the passive form, we can say something like this:
George is very focussed. I’m sure he’ll do well in all his exams.
However, we cannot say that George is ‘concentrated’. In English, we use the word concentrated when we describe something that is ‘stronger’ because water or some other element has been removed.
I don’t drink concentrated orange juice. I prefer freshly-squeezed juice.