1 I have met the boy helping you with the work yesterday

-->The boy

2 The sales of mobile phone have increased considerably since 2005

-->there has

3 the match was postponed to the following Sunday because the weather

-->Owning to

4 Parents are often proud of their children's good result(pride)

-->

5 Brussels us a good place to spend a weekend.I've visited it serveral time already

-->Brussels

6 Only when something major and comprehensive is done can we prevent war , disease and poverty

-->In order

7 Secondary school is free in Britain

-->You don't have to

8 Mr.Taylor fixed the sewing machine for my mother

--> My mother got

9 As the class representative,I would like to welcome you

-->On

10 We were told to wait here by the director

-->It was

11 Speaking during the exam is forbidden

-->You

12 He is studying English very hard .He want to study at Harvard university

-->With a view............

13 She can sing and play the piano well

-->Not only.....................