Ex23: Put the verbs into the passive form:
1. Bottom of Form1. Most of the Earth’s surface (cover) ............... by water.
2. The first festival (hold) ............. nearly eight hundred years ago.
3. There’s someone behind us.I think we (follow) .................
4. An interesting book (read) ................. by Lan at the moment.
5. This bike (use) ............... for more than six years.
6. Nowadays, many historical places (destroy) .................. seriously.
7. A new textbook (publish) ............... next month.
8. The Eiffel Tower is in Paris.It (visit) ........... by millions of people every year.
9. Since the 1980s more and more paper(recycle) ................
10. Tet holiday in Viet Nam (celebrate) .................... around January and February.