Final answer:
The main idea is President Ford honoring the United States' two hundredth birthday by tapping the Liberty Bell, symbolizing independence and paying tribute to the original thirteen colonies.
Step-by-step explanation:
The main idea of the paragraph about President Ford's celebration of the United States' two hundredth birthday is the ringing the Liberty Bell in honor of the United States' two hundredth birthday. This event symbolizes the nation's commemoration of its independence and pays tribute to the original thirteen colonies that fought for liberty. President Ford's act of tapping the Liberty Bell thirteen times at Independence Hall in Philadelphia represents a ceremonial gesture to honor the historic significance of the Declaration of Independence and the fight for freedom that began in 1776.