We'll have a picnic today if it doesn't rain. So it will probably rain like cats and dogs, since we really do want to have a picnic. Harry always gets a headache the day after a party. There was a party last night. It hasn't rained once during the past three weeks, so it probably won't rain again today.
All human beings are mortal.
Jorge is a human being. Therefore, Jorge is mortal. Emily has studied logic. Harold's eyebrow always twitches when he is lying. So he must be lying now, since his eyebrow is twitching.