present
I concentrate
You concentrate
He concentrates
She concentrates
It concentrates
We concentrate
They concentrate
past
I concentrated
You concentrated
He concentrated
She concentrated
It concentrated
We concentrated
They concentrated
future
I will concentrate
You will concentrate
He will concentrate
She will concentrate
It will concentrate
We will concentrate
They will concentrate
conditional
I would concentrate
You would concentrate
He would concentrate
She would concentrate
It would concentrate
We would concentrate
They would concentrate