[解析]
(1)A.推理判断题。根据CS50's Introduction to Computer Science部分Length:14 weeks Effort:6 hours per week.时长:14周工作时间:每周6小时。可知, "CS50's Introduction to Computer Science"总共需要84小时的学习时间;根据Masterpieces of WorldLiterature部分Length:12 weeks Effort:8 hours per week.时长:12周工作时间:每周8小时。可知, "Masterpieces of WorldLiterature"总共需要96小时的学习时间;根据The Health Effects of Climate Change部分Length:9 weeks Effort:10 hours perweek.工作时间:9周工作时间:每周10小时。可知, "The Health Effects of Climate Change"总共需要90个小时的学习时间;根据Global China:From the Mongols to the Ming部分Length:15 weeks Effort:6 hours per week.时长:15周工作时间:每周6小时。可知,"Global China:From the Mongols to the Ming"总共需要90个小时的学习时间。所以"Masterpieces of World Literature"需要最多的学习时间。故选A。
(2)D.数字计算题。根据Global China:From the Mongols to the Ming部分How the Mongols created the greatest empirein human history.蒙古人如何创造了人类历史上最伟大的帝国;How the Ming Dynasty established a new global economy.明朝如何建立新的全球经济。可知,这门课是关于历史的,再根据"Add a Verified Crtificate for¥643"(已验证证书需添加¥643)。可知,学生应该付¥643获取有关历史的已验证证书。故选D。
(3)B.推理判断题。根据The Health Effects of Climate Change部分Instructors:Ashish Jha"(讲师:Ashish Jha).Ashish Jha教授的是"气候变化对健康的影响这]课。可知,从Ashish Jha教授那里可以学到气候变化如何影响人类。故选B。