3.English is easy to learn
->It is easy to learn English
4.Don’t leave the lights on all night,you will waste electricity.
->If youdon't leave the lights on all night , you will waste electricity

6.The policeman does not run so fast as the thief (THAN)
-> The thief runs faster than the policeman does
7.I haven’t seen this man here before(FIRST)
-> It is the first time I have seen this man
8.The novel is very interesting.(FIND)
-> I find it interesting to read