problem about "darn" 1.Well I'll be darned! You actually showed up! 2.I’ll be darned if the train didn't leave until an hour later. 3.I offered to help, but darned if she didn't do the whole thing herself. There are some example sentences about "darn" from the Webster's Learner's Dictionary. I am a little confused. Because if the things darned me have happened，then why say“I‘ll be”？