Random Riddle: Consecutive Letters

Complete the words below using three consecutive letters in alphabetical order, e.g., _ _ A _ U S; add A B and C it would become ABACUS.

1. _ _ R _ E S,

2. D O _ I _ _,

3. _ R A _ I _,

4. _ O U _ _ T,

5. _ _ A _ U E,

6. _ A Y _ A _.
 

Random Riddle: Consecutive Letters