11. Since its invention, the Internet (change)___________________ our ways of communication a lot. 12. You can use online social network websites (connect up)_________________________ with friends and relatives. 13. While I (walk)______________________ home yesterday, I (see) _________________ two masked men run out of the shop. 14. The White House (burn)_____________________ down by British troops in the War of 1812. 15. Many people spend hours (surf)_____________ the Internet every day.