Present
I    understand
you  understand
he   understands
we   understand
you  understand
they understand

Perfect
I    have understood
you  have understood
he   has understood
we   have understood
you  have understood
they have understood

Past
I    understood
you  understood
he   understood
we   understood
you  understood
they understood

Pluperfect
I    had understood
you  had understood
he   had understood
we   had understood
you  had understood
they had understood

Future
I    will understand
you  will understand
he   will understand
we   will understand
you  will understand
they will understand

Future perfect
I    will have understood
you  will have understood
he   will have understood
we   will have understood
you  will have understood
they will have understood

Present
I    understand
you  understand
he   understand
we   understand
you  understand
they understand

Present
I    have understood
you  have understood
he   have understood
we   have understood
you  have understood
they have understood

Imperfect
I    understood
you  understood
he   understood
we   understood
you  understood
they understood

Pluperfect
I    had understood
you  had understood
he   had understood
we   had understood
you  had understood
they had understood

Present
I    would understand
you  would understand
he   would understand
we   would understand
you  would understand
they would understand

Perfect
I    would have understood
you  would have understood
he   would have understood
we   would have understood
you  would have understood
they would have understood

Present
I    am understanding
you  are understanding
he   is understanding
we   are understanding
you  are understanding
they are understanding

Perfect
I    have been understanding
you  have been understanding
he   has been understanding
we   have been understanding
you  have been understanding
they have been understanding

Past
I    was understanding
you  were understanding
he   was understanding
we   were understanding
you  were understanding
they were understanding

Pluperfect
I    had been understanding
you  had been understanding
he   had been understanding
we   had been understanding
you  had been understanding
they had been understanding

Future
I    will be understanding
you  will be understanding
he   will be understanding
we   will be understanding
you  will be understanding
they will be understanding

Future perfect
I    will have been understanding
you  will have been understanding
he   will have been understanding
we   will have been understanding
you  will have been understanding
they will have been understanding

Present
I    would be understanding
you  would be understanding
he   would be understanding
we   would be understanding
you  would be understanding
they would be understanding

Perfect
I    would have been understanding
you  would have been understanding
he   would have been understanding
we   would have been understanding
you  would have been understanding
they would have been understanding