1. What do the following words have in common?

MET
MAN
BUS
NET

2. What do the following words have in common?

PAN
VOW
BAG
CHAP
CART
PAST

HINTS:
1. The same three letters can be added to each word.
2. The same two letters can be added to each word.

Answers:

1. The letters TLE can be added to each word to form a new one"

METTLE
MANTLE
BUSTLE
NETTLE

2. The letters EL can be added to each word to form a new one:

PANEL
VOWEL
BAGEL
CHAPEL
CARTEL
PASTEL