1. It is reported that a large number of students have dropping out of school in recent years.
=> have dropping => have dropped
2.It's nearly ten years since he has suddenly left the town.
=> has suddenly left => suddenly left
3. I won't do anything before I heard any news from you.
=>heard => hear
4.Don't touch anything until the police come, do you?
=> do you => will you
5.Because an increase in sales, the company is planning to expand its business.
=> Because => Because of
6.The children looked happily as their mother was coming home from work.
=> happily => happy
7. A lot of information sent to the newspaper are not true.
=> are not => is not
8. He wouldn't accept that hard job if he doesn't need the money.
=> doesn’t need => didn’t need
9.Today we know that the earth is one of nine planets who orbit the sun.
=> who => which
10. Mr. Jones is an experienced teacher who has been in this school since thirty years.
=> since => for