The professor assigned a set book for the course, which students were expected to read before each lecture.
教授为课程指定了一本参考书，要求学生在每次讲座前阅读。
Students found the set book quite challenging and spent a lot of time discussing it in study groups.
学生们发现指定的参考书相当有挑战性，花了很多时间在学习小组中讨论。