Answer:
16. The new car is a blue-and-white four-door sedan.
17. Small cars use less gasoline than large vehicles.
18. Some owners of the large cars have traded them for smaller models.
19. Dual air bags make the car very safe.
20. Many larger cars have an extra tax on them.
Step-by-step explanation:
I underlined the subjects and verbs. Depending on your teacher, "some" might be considered the subject in sentence 18