1. 13 is believed to be an unlucky number

2.  As she was ill, she couldn’t come to class

3. She doesn't study hard.

4. Honda is a company. It makes a lot of cars.

5. He is known to have been in prison several times.

1. People believe that 13 is an unlucky number

=> 12 is believed to be an unlucky mumber

2. She couldn't come to class because of her illness

=> As she was ill, she couldn’t come to class

3. She needs to study harder

=> She doesn't study harder

3. Honda is a company which make a lot of cars

-> Honda is where a lot of cars are made 

4. It is common knowledge that he has been in prison several times

-> He is known to have been in prison several times