Direct objects are only found in sentences with action verbs! :)
The 1920's was a time of sensational economic growth and progress. Mass produced goods such as clothing, radios and cars were in abundance. The stock market boomed and most Americans benefited. But there was also economic inequality, thus the prosperity of the 1920's was unsustainable.
Answer:
the villians/bad guy of the story
Fifty cents is a plural noun since it is talking about more than one cent. In the example, you would say, "fifty cents <em>is </em>how much I owe you".