(1) I hope that some of the wonderful teachers will answer you.
(2) I, too, find the subjunctive very confusing.
(3) According to Grammar in Use by Mr. Raymond Murphy, you may
use the subjunctive for the present, past, or future.
(a) Here are his insist examples:
They insisted that we have dinner with them.
I insisted that he have dinner with me.
I insist that you come with us.
They insisted that I go with them.
I insisted that something be done [passive] about the problem.
MAYBE !!! The correct answer is (a) The teacher insisted that she be
on time. (That is what I think, but I could easily be wrong.)
TWO IMPORTANT POINTS:
1. Mr. Murphy's book is based on American English. Maybe our
British friends have a different idea about the subjunctive.
2. Insist does not always take the subjunctive:
The teacher insisted that Martha was late. = Martha said that she was on
time. The teacher said: No way!!! You were absolutely, definitely late!!!
Please keep posting subjunctive questions as often as you like. There are
many people here who understand the subjunctive, and they will give you
Student or Learner