Decades of change

What two types of revolution does the article mention? When did

they happen?

How many centuries are mentioned in the article? Which ones?

What types of technology are mentioned in the first paragraph?

What were two important developments in communications

in the 21st century?

How did entertainment technology change in the 21st century?

Did most of the progress in IT mentioned in the article happen in the first or the second decade

of the 21st century?

What had already happened when the 20th century began?