Evaluate:
The law is very effective in achieving justice, as can be seen from its reform of law.
Assess:
This experiment is not very effective, as can be seen by many things such as cases around the world, results obtained, and a large number of other factors.
Discuss:
The study of ancient history allows us to learn many things about the past. Though there are issues, such as conservation and reconstruction. Both have positive and negative points, and both are important (you would then go on to talk about these points).
I hope that helped and that I didn't screw them up lol.