II. Choose the best answer to complete each sentence.
11. National parks help to ................... endangered species.
12. A large hydroelectric ............................. was built on the River Danube.
13. Cuc Phuong National park is ................................ - 160km South West of Ha Noi.
14. A forest fire ........................... valuable wood, wildlife and good soil in Ca Mau some years ago.
15. You look very tired, you .......................... stay at home and relax.
16. Tom really ..................... go out. He has too much homework to do.
17. Farmers earn their livings mainly by doing .......................
18. What should we do to reduce the level of environmental .................................
19. Vietnam team was warmly welcomed by the .......................... country.
20. Hanoi National University was ............................. one hundred years ago.