Hello Would you please tell me what 's the difference between by and until in negative statements like these ones? A- I didn't get up by nine o'clock. B- I didn't get up until nine o'clock. C- He won't be back by Friday. D- He won't be back until Friday. E- They won't publish my book by March. F- They won't publish my book until March. G- I won't work by the age of 30. H- I won't work until the age of 30. Thank you.