https://online2.tingclass.net/lesson/shi0529/0009/9907/746.mp3
https://image.tingclass.net/statics/js/2012
讲解文本：
instruct 指导，教
instructive 有指导意义的，有教育性、启发性的
Mike's answer is very instructive.
麦克的回答很有指导意义。
Mary is the best teacher in our school. I like her instructive lessons.
玛丽是我们学校最好的老师，我很喜欢她那些很有启发性的课程。
