閱讀測驗        Humans have been drinking coffee for centuries, but there have been mixedmessages about its effects on human health for decades. In the past, coffee wasassociated with increased health risks. However, research from the last decade hasfound that drinking coffee may actually benefit our health.Coffee has often been seen as a bad thing. Research findings from the 1980s and90s reported that people who drank coffee had a higher risk of heart disease. Coffeealso has been associated with an increased risk of cancer because of a certain substanceit contains. The same substance can be found in foods including toast, cakes, and chips.        However, according to Marc Gunter, a head researcher at the International Agencyfor Research on Cancer (IARC), new larger-scale studies have emerged over the lastdecade providing data from hundreds of thousands of coffee-drinkers. These datasuggest that coffee consumption may have more health benefits than risks. In 2016, theIARC reported that coffee is not associated with cancer, unless it is drunk very hot–above 65°C. Other research has found that coffee may have a protective effect； cancerpatients who drank coffee tended to have less serious conditions than those who didnot drink it.        In 2017, Gunter published a study that looked into the coffee-drinking habits ofhalf a million people across Europe and their health conditions over a period of 16years. It turned out that those who drank more coffee had a lower risk of dying fromheart disease, stroke, and cancer. These findings echo those from other parts of theworld, including the U.S. Gunter says there is enough evidence to confirm that peoplewho drink up to four cups of coffee a day have fewer diseases compared to those whodo not drink any. Moreover, drinking a cup of coffee every four hours can sustain yourpositive mood throughout the day.         Studies from the last ten years have shown support for the common belief thatcaffeine is the most popular psychoactive drug in the world. That is to say, drinkingcoffee, which is a natural source of caffeine, may improve a person’s mood and levelof attention. So if you feel exhausted or overwhelmed at work, perhaps a coffee breakis all it takes to bring back positive energy.
【題組】21. What is the main idea of this passage?
(A) Researchers believe that coffee can help prevent heart disease.
(B) Results of a study concluded that coffee does not cause cancer.
(C) Research findings suggested that coffee has an effect on mood.
(D) Recent studies have shown that coffee may bring health benefits.