Complete each sentence so that it means the same as the sentence above

VII. Complete each sentence so that it means the same as the sentence above. (1.5points)
1. It is essential to revise our lessons carefully before the exam.
    We must     
2. My brother can run fast.
My brother is          
3. She was tired, so she went to bed early.
Because    
4. We use the car all time, and we make the air dirty.
If we     
5. No river in the world is longer than the Nile.
The Nile is