Part 1:Complet each blank with one given word.There are more words than needed.
of which where have because on though pollution
1.Viet Nam,..................... os in south-east Asia,exports a lot of rice
2,I don't believe UFOs exist ....................articles and reports in newspapers talk lots about UFO appearance.
3.Do whatever you can to conserve oil ............................. oil is a valuable resource
4.You shouldn't leave lights,air-conditioners and televisions ................... when no one is in the room
5.It's very kind .................you to help me
