5 I have read book twice because it is very interesting 
-> this book is very interesting, so I have read it twice 
6 minh won' t pass the final exam if he doesn't learn hardeer 
-> unless Minh learn harder, he won't pass the final exam 
7 scientists have reported that there is far too much pollution nowadays in city areas 
-> it has been reported by scientists that there is.... areas
8 my sister likes reading books better than watching IV in her free time 
-> my sister prefers reading books to watching TV in her free time 
9 my mother sometimes wants to come back to her childhood 
-> my mother sometimes wishes she could come back to her childhood