1.slowly
2.safely
3.daily
4.suddenly
5.carefully
6.weekly
7.lately
8.truthfully
9.hopefully
10.powerful
11.peaceful
12.beautiful
13.cheerful
14.painful
15.thoughtful
16.action
17.location
18.invention
19.correction
20.pollution

Bonus Words:
1. grateful
2. suspenseful
3. completely
4. exactly
5. separation