Identify subjects and verbs.
8. many men and women picked their teeth clean after meals
9. the stems of feathers or special tooth picks were employed for this.
10. brass or silver toothpicks were safer than animal-hair toothbrushes.
11. germs developed on animal bristles, leading to frequent infections.
12. there was no solution to this problem until the 1930s.
13. the discovery of nylon led to a big change in the toothbrush industry.
14. nylon was tough and resisted the growth of germs.
15. the first nylon-bristle brushes were sold in the united states in 1938.
16. unfortunately, they were very hard on gums.
17. soft gum tissue scratched and bled easily.
18. in the 1950s, a new, softer version of the nylon toothbrush was developed.
19. it cost five times as much as the older, harder brushes.
20. with this development, national dental care improved.