Here are the appropriate responses to fill in the blanks:
- to vote
- poll tax
- literacy test
So the completed text would read:
African Americans in the South were prevented from being able to vote. Many Southern states required voters to pay a fee before they could vote called a poll tax. Because many African Americans could not afford to pay, they could not vote. Another way was to make voters take a literacy test where they had to read and explain parts of the Constitution. Since most African Americans had little education, the tests prevented many from voting.