Present
I strengthen
you strengthen
he strengthens
we strengthen
you strengthen
they strengthen

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

Past
I strengthened
you strengthened
he strengthened
we strengthened
you strengthened
they strengthened

Pluperfect
I had strengthened
you had strengthened
he had strengthened
we had strengthened
you had strengthened
they had strengthened

Future
I will strengthen
you will strengthen
he will strengthen
we will strengthen
you will strengthen
they will strengthen

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

Present
I strengthen
you strengthen
he strengthen
we strengthen
you strengthen
they strengthen

Present
I have strengthened
you have strengthened
he have strengthened
we have strengthened
you have strengthened
they have strengthened

Imperfect
I strengthened
you strengthened
he strengthened
we strengthened
you strengthened
they strengthened

Pluperfect
I had strengthened
you had strengthened
he had strengthened
we had strengthened
you had strengthened
they had strengthened

Present
I would strengthen
you would strengthen
he would strengthen
we would strengthen
you would strengthen
they would strengthen

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

you strengthen
we Let's strengthen
you strengthen

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

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

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

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

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

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

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

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