Caffeine also has a halflife of around 6 hours, so if you drank a standard coffee with around 150mg of caffeine, after about 6 hours there will only be 75mg left in your system and you'll be feeling half of the effect.

咖啡因也有大约6个小时的半衰期，所以如果你喝了一杯标准规格的，含大约150毫克咖啡因的咖啡，在6小时后就仅有75毫克留在身体内，而咖啡因的影响也会减半。