Conditional sentence or we may say "if Clause" and Subjunctive. It is usually a desire/wants/needs that can't be fulfilled by someone, and It sometimes means 'regret' in context. I used this file to teach in SMK (vocational high school)

1. Reference:
Betty Schrampfer Azar Page 413

2.  1. What is Conditional sentence?
 2. What is Subjunctive?

5. Conditional Sentence is also called “IF CLAUSE”
See page
413

6. Do exercise 11, 12, & 13 (page 421)

7. Example:
A.“Were I you, I wouldn’t do that”
Were I you = If I were you
A.“Had I known, I would have told you”
Had I known = If I had known
See page 424

11.  Do exercise 11, 12, 13 page 421