1.What do the following words have in common?

KIN
PRO
WAN
CROW
WOO


2. What do the following words have in common?

LAW
LINE
LEAVE
DOZE
MOO
TOW

Answers:

1. Each word can be changed into a new one by adding D at the end. 
2. Each word can be changed into a new one by adding N at the end.