After a certain change, each of the words below can be preceded by the same three letters to form new words.

1. SCENT
2. SEED
3. DUCKED
4. TRACKED
5. SENSES

HINT:
The words are all homophones.

Answer:

Each word has a homophone that can be preceded by CON to make a new word:

1. CONSENT
2. CONCEDE
3. CONDUCT
4. CONTRACT
5. CONCENSUS

Credit:
GAMES Magazine
November, 1083
Robert Leighton
CON QUEST