Subjunctive doubt , denial & negation

Question

Can someone provide an example for each of the following forms of the subjunctive?
Doubt...
Denial...
Negation..

Answer 1

There aren't any, really. Those feelings are actually provided by the main verb in indicative, and not by the verb in subjunctive. If you need to express doubt, you use "to doubt", "not to know", "to ignore", or something similar. If you want a denial, say "no", etc.

Dudo que vengan
No quiero que vengan
No creo que vengan

Sometimes I wonder why don't they invent more "types of subjunctive", such as:

Comería lo que me dieran = subjunctive of eating
Me rascaría hasta que me doliera = subjunctive of scratching
Estornudo más de lo que puedas imaginarte = subjunctive of sneezing

Subjunctive is used simply when you don't want to declare something. Check other posts about "subjunctive" and "declaration".