Complex sentence: In some particular functional drinks, particularly energy drinks, the caffeine content can be high, ranging from 0 to 141.1 milligrams per serving, of which an average 8-ounce cup of coffee contains about 133 mg of caffeine.
Split into simpler sentences: In some particular functional drinks, particularly energy drinks, the caffeine content can be high, ranging from 0 to 141.1 milligrams per serving. This can be more than an average 8-ounce cup of coffee, which contains about 133 mg of caffeine.