If you _ (brush / not) your teeth after meals, you _ (have) cavities.

1. were shown

2. are developed

3. is being discussed

4. is being built

5. are devoted

6. is known

7. are being prepared

8. were done

9. was being cooked

10. are being sold 

are they your friends? -yes, they are

is he your brother? - yes, he is

can he ride a bike? - no, he can't

do you want to play with the ball? - no, i don't

does she roller-skate well? - no, she doesn't

does your friend want to play the piano? - yes, he does