1. You cannot gain anything without efforts.
--> Nothing .can be gained without efforts.....
2. Due to his carelessness, he broke the most precious vase in his father's porcelain collection.
--> It was careless ..of him to break the most precious vase in his father's porcelain collection....
3. No other magazine in the USA is more popular than people.
--> People ..is the most popular ...in the USA...
4. When did your student start doing his research on Applied Linguistic?
--> How long ....has your student.done ..his research on Applied Linguistic?
5. They wanted to know whether i had know him when i had been at college.
--> They asked me, " ...Have you known him when you has been . at college...."