1. What do the following words have in common?

MAIN
CENT
NATION

NUT
SAGE

WAGER
YEN
OR

2. What do the following words have in common?

SERVE

LITERATE

SCENE

LONG

HINTS:

1. The same two letters, in the same, consecutive order and placed in the same position, will change each word to a new one.
2. Same as HINT 1, except that the two letters are different.

Answers:

1. Each word, when preceded by DO, becomes a new word.
2. Each word, when preceded by OB, becomes a new word.