Answers:
`3.` She didn’t eat much though she was hungry.
`-` Despite her hunger, she didn't eat much.
`4.` The train was late because the fog was thick.
`-` Because of the thick fog, the train was late.
`5.` I accepted the job although the salary was low.
`-` In spite of the slow salary, i accepted the job.
`6`. The plane couldn’t take off because the weather was bad.
`-` Because of the bad weather, the plane couldn’t take off.