I've been learning about conditional sentences and I want to propose my understanding and I hope somebody would tell me if these are wrong.
1. If X aux. verb, X would have Y always uses auxilary verb had
- I didn't vote in the election, but if I had, I would have voted for Senator Todd.
- I called my husband to tell him I would be late. If I hadn't, he would have gotten worried about me.
2. If the question starts with "Are" the negative answer must be No, but if X were
- Are you hungry? No, but if I were ....
3. If the question starts with "Do" the negative answer must be No, but if X did
- Do you speak Spanish? No, but if I did ....
4. If the question starts with "Did" the negative answer must be No, but if X had
- Did you forget to bring your grammar book? No, but if I had ....
That's all. I need to know whether my understanding is correct or not and please correct me with an example, so I can understand the topic.
Note: X is a subject and Y is an arbitrary thing that being done by X.