present
I understand
You understand
He understands
She understands
It understands
We understand
They understand
past
I understood
You understood
He understood
She understood
It understood
We understood
They understood
future
I will understand
You will understand
He will understand
She will understand
It will understand
We will understand
They will understand
conditional
I would understand
You would understand
He would understand
She would understand
It would understand
We would understand
They would understand