1. What do the following words have in common?

ROOM
SEAT
OFFICE
ROW
PAGE

2. What do the following words have in common?

CUR
TOR
DETER

HINTS:
1. #1: Each word can be preceded by two different words.
    #2: The two preceding words are opposites

2. All three words can be followed by the same four letters, which make up a word in their own right.

Answers:

1. Each word can be preceded by both FRONT and BACK. 

2. Each word can be followed be RENT:

CURRENT / TORRENT /  DETERRENT