1. What do these three words have in common?

GUILT / GUEST / PLAGUE

2. What do these six phrases have in common?

Radio waves
Coming out ahead
Got exasperated
Remain even
Foregone conclusion
Trade law area

3. What do the following words have in common?

CAN

BYE

BOO

TOM

HINTS:
1. Replace the same letter in each word with another letter (the same in each word).
2. Think US States.

Answers:

1. Replacing the G in each word with a Q creates a different word:

QUILT/QUEST/PLAQUE

2. Hidden in each phrase is the name of a state.

Iowa/Utah/Texas/Maine/Oregon/Delaware

3. They are often repeated, one after the other.