The Gerbil had ( forgot, forget, forgotten )
where its tail was.

I (were, was, am ) suffering last week,
but I have improved since then.

This morning I ( is, am, will ) be going to
work in a spaceship.

You ( will, would, have ) hear the result of
the competition next week.

( Write, Wrote, Writing ) clearly so people can
understand what you mean.