The pair of sentences that best completes the diagram showing the course of the French Revolution is "a mob storms and capture the Bastille, French leaders form the Estates General.".
In European history, the revolution was a revolutionary movement that shook France in 1787 and denoted the end of the ancient régime in France. During the 17th centuries, the Bastille in question was a historic stronghold on the east side of Paris that has become a French state jail and a house of imprisonment for notable accused persons of multiple crimes.
However, the Bastille no longer exists, but some of its remnants can be found in Paris. As a result, "a mob storms and captures the Bastille, French leaders form the Estates General" is the combination of lines that best completes the diagram depicting the path of the French Revolution.