1. 用方框中所给词的适当形式填空

invent    health  pollute   ill  communicate

1. （1）   between people who speak different languages is difficult．

3. （2） Which do you think is the most useful ，the computer, the phone or the plane?

5. （3） We should reduce by reusing paper．

7. （4） Junk food is ．Don't eat it．

9. （5） The most important thing is that her daughter' has been cured．