four opponent powers

Four points to purify destructive karma. These are regret, generating bodhicitta and taking refuge, engaging in a remedial action, and making a determination not to do the harmful action again. See chapter 10 of The Foundation of Buddhist Practice.

Subtle impermanence
Answering questions from retreat participants and teaching on understanding impermanence and generating love and compassion
Four opponent powers
Covering Verses 2.27-2.31 on the four opponent powers of purification.
Verbal non-virtues
Continuing the explanation of ten non-virtues, covering the third physical non-virtue and the first three verbal non-virtues.
The four opponent powers
Explaining the four opponent powers of purification, and encouraging us to take responsibility for our actions in a way that frees us from guilt and anger.
Discerning virtuous from nonvirtuous actions
Completing "The Weight of Karma", teaching "Discerning Virtuous from Nonvirtuous Actions", and starting "Karma and Current Ethical Issues"