1. It's necesssary for you to attend the course.
2. You should turn down the volume at night.
3. So far I've written ten pages of the letter.
4. You must not turn on that machine.
5. Since we got up late, we missed the first period.
6. They failed the exam because they are so lazy
7. If you don’t do exercise , you will have fat in your blood.
8. I suggest that you should stop here