1. The same four-letter word will complete the words ending in the letters below.

_ _ _ _ N
_ _ _ _ R
_ _ _ _ T

2. The same six-letter word will complete the partial words below.

BA _ _ _ _ _
CA _ _ _ _ _
DU _ _ _ _ _
FA _ _ _ _ _
LA _ _ _ _ _
RU _ _ _ _ _
TA _ _ _ _ _

Answers:

1. The word is COVE:

COVEN
COVER
COVET 

2. The word is STING.