1. 用所给词的适当形式填空

1. （1） They have made a huge effort(help) us．
   

3. （2） We often asked the workers for(advise)．

5. （3） I advise(wait)till the right time．

7. （4） Animals have different kinds of methods of(communicate)．

9. （5） It's hard to imagine that one day English may not be the world's (lead)language．