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