1)I think I have seen him somewhere before.
2)He'll be ready in a minute.He is cleaning his shoes
3)We* ll go to the theatre tonight
4)They couldn't leave the studio when I called because they were watching a film ( здесь пропущен глагол, возможен и такой вариант they were going to a film)???
5)When I shouted, they jumped off the roof and ran away
I have seen.
is cleaning.
went
were filming.
had jumped off, ran.