Answer:
3) Radioactive material in the Garigliano River (made) underwater searches there dangerous. - past
4) Many students of archaeology (will have) completed an archaeological dig by graduation. - future perfect
5) I am happy __ Leonardo da Vinci's Mona Lisa - To have viewed
6) Da Vinci was one of the most interesting artists __ during the Italian Renaissance. - to have lived
hope this helps
Explanation:
