Affirmation, negation and imperative

1. Affirmation
         a) Without specific non-manual marking
         b) Affirmative headnod
         c) Affirmative signs
2. Negation
         a) Headshake
         b) Headshake and negative sign
                   b.1 Sentence negation
                   b.2 Signs incorporating negation
3. Imperative
         a) Basic form
         b) Alternative forms for command expression

And, third, there are sentences containing affirmative signs: "yes", "logical", "sure", "of course!", "normal", etc.

    "My sister is pregnant. I'm sure it'll be a girl."
    "Shall I close the window? Yes, the air bothers me."
    "If you skip so many classes it's normal for you to fail."