1. 句型转换

1. （1） The boss made them work the whole night. (变为被动语态)
   
3. （2） He wanted to shut the window. Tell him not to shut the window. (合并句子)
   
5. （3） It is known that she has been working on the problem for many years. (变为简单句)
   
7. （4） It seems that he is eating something. (变为简单句)
   
9. （5） To study two languages is very hard. (用it作形式主语)
   
11. （6） He felt it was necessary to help those in need. (变为简单句)
    
13. （7） We believe that he is guilty. (变为简单句)
    
15. （8） He ran fast so that he could catch the first bus. (变为简单句)
    
17. （9） He searched the room but found nothing. (变为简单句)
    
19. （10） The box is so heavy that we can't carry it. (变为简单句)