Problem: If "John promised Bill to leave, so an hour later he left.", is "John left." correct?

Answer: yes

Problem: If "It is not easy to space buttonholes exactly the same distance apart, and it is very difficult to cut them precisely the right size. The tiniest slip of the scissors will make the hole too large, and even one thread uncut will leave it too small.", is "Even one thread uncut will leave the hole too small." correct?

Answer: yes

Problem: If "Dr. Adams informed Kate that she had retired and presented several options for future treatment.", is "Kate had retired and presented several options for future treatment." correct?

Answer:
no