1. Tennis was being played by them from four till five
2. A number of important experiments have been carried out by them in this Laboratory
3. Central Africa was explored by Livingstone in the 19th century
5. ‘l stay
6. ‘l leave
7. Will go
8. are going to celebrate
9. ‘l wait
10. Are working
Надеюсь помогла
И ещё надеюсь что знания не переделаюсь мои абзацы в сплошной текст