This is a "word ladder" to drill your knowledge of USA chain restaurants. By "word ladder", I mean that if a letter appears more than once in a line and in adjacent lines, typing that letter in one blank will make your appear in appropriate blanks in the line and adjacent lines.
To see what I mean: The first restaurant is QDOBA. Fill in the missing A and see what happens.
List of big restaurant chains from LeadsDeposit via Liang&Andris Measuring McCities.