VOA慢速英语:What is Pneumonia and How Do You Get it?

fungi - n. plural for the word fungus. any one of a group of living things that often look like plants, but have no flowers, and that live on dead or decaying things

coughing - v. forcing air through one's throat with short, loud noises

immune system - n. the body's natural defenses against disease

crackling - adj. a series of short, sharp noises

bubbling - adj. of or related to small balls of air or gas inside a liquid

rumbling - adj. a low, heavy sound or series of sounds