Plesiosarus (to be) a reptile that (to live) during the Jurassic period.
It (not be) a dinosaur, but a sea creature that (to be) from three to eighteen metres long. It (to have) a small head, a long neck and tail and four flippers. Plesiosaurus (can) probably walk on land. Some people believe that the Loch Ness Monster is a Plesiosaurus!