20.4 Vocab: Last ones this chapter!
38. landlord: a person who owns a building and rents it to a family.
39. tenant: a person who rents an apartment from a landlord.
40. tenement: 5 or 6 story buildings in the cities
41. slums: a poor, dirty place to live
42. ventilation: letting fresh air come into a room
43. Sanitary: clean and healthy
44. Unsanitary: dirty and unhealthy
45. Miserable: Very sad
46. Population: the number of people living in a country
47. Overpopulated: too many people living in a place
