Lesson 14, Exercise 10 - Bill Part 2

Watch the video. Answer the question.
They're awful. They're the source of the entire world's problems.
Source (adjective): origin, root, beginning.

For example, mountains and springs are the source (origin) of rivers.

Tap on any word once (mobile), or double-click on any word (computer), to read an English definition. If you need an approximate translation to your own language, the Google Translate button is available at the top of the screen.