Participants took capsules containing caffeine equal to about four cups of coffee on one day and then identical capsules that contained a placebo on another day.

受试者第一天服用咖啡因含量相当于四杯咖啡的咖啡因胶囊，然后第二天服用外观相同的含安慰剂的胶囊。

youdao

Here is your cough syrup. Take one capful every 4 hours until your cough goes away. And take one of these capsules a day, after eating.

这是你的咳嗽药水。每四小时吃一瓶盖满直到不会咳嗽为止。这些胶囊每种一天吃一粒，饭后吃。

youdao

Here is your cough syrup. Take one capful every 4 hours until your cough goes away. And take one of these capsules a day, after eating.

这是你的咳嗽药水。每四小时吃一瓶盖满直到不会咳嗽为止。这些胶囊每种一天吃一粒，饭后吃。

youdao