1. What do the following words have in common?

SON

WED
STEP

2. What do the following words have in common?

BURN

SPICE

GUST

THOR

HINTS:

1. It has to do with the middle letter of each word.

2. The same two letters, added in the same place, will create new words.

Answers:

1. Doubling the middle letter of each clue will give a new word:

SOON/WEED/STEEP

2. Each word can be preceded by AU:

AUBURN/AUSPICE/AUGUST/AUTHOR