NY Times Crossword
November 30, 2014
Matt Ginsberg
(Title shown in HINT #3)

The same letters, in the same, consecutive order, will change each word below into a new one. What are the letters and the new words?

SHY
LIES
LEER
SHOW
SERENE

HINTS:
#1: The change involves inserting the same two letters somewhere into each word.
#2: The first of the two letters is A.
#3: The title of this puzzle is COMMERCIAL FREE.

Answers:

The letters AD can be inserted somewhere in each word to make a new one:

SHADY
LADIES
LEADER
SHADOW
SERENADE

Note on HINT #3: COMMERCIAL FREE - NO ADS