It's disappointing that they've used the same type numbers 1, 2 and 3 for two completely different structures.
It's strange that they've called the last six types "mixed" but not given a label to the first three.
The actual content looks good on a brief inspection, but using this system, one couldn't refer to a type 2 conditional and be understood.
Is it used anywhere? What's the source?
Student or Learner