Complex negative conditional structures including multiple negation
Q1. ___ you study, you will not pass
UNLESS you study means IF YOU DO NOT STUDY. Negation is embedded. Failure looms.
Q2. He was careful ___ he make a single error
LEST means SO THAT ... NOT. Errors were avoided. Care was taken.
Q3. ___ your cooperation, this would have been impossible
WITHOUT introduces absence. Cooperation was given. Success followed.
Q4. Not ___ you apologised a thousand times would I forgive you
NOT IF emphasises absolute refusal. Apologies are insufficient. Forgiveness is withheld.
Q5. Which is the most formal negative conditional?
LEST is archaic and highly formal. Legal and liturgical contexts preserve it. Modern speech forgets.