Online classes began to be popularized just a few decades ago. They are advertised as a way for adults to finish their education and students to learn the material at their own pace—it is far more compatible for people with busy schedules.

        But after being enrolled in an online course last fall semester, I came to realize online classes were merely a means to fulfil course requirements.

         First of all, students lack the desire to learn, and they simply complete their assignments to receive credit for a passing grade rather than genuinely engage with the course material.

        As online courses tend to have more than 100 students, most of the assignments are short and simple. They are not designed for students to interact with the material in depth but designed to be graded easily to accommodate such a large number of students.

         Perhaps the biggest disadvantage of taking an online class is the absence of face-to-face interaction between the teacher and their students. Live sessions are infrequent and are often scheduled during the middle of the day when students have to attend other classes or work. The office hours of the professor may also be during inconvenient times for many students as well. Most interaction with the professor has to be through email which is often impersonal. It is nearly impossible for students to build a relationship with their professor.

        There is also little interaction amongst students. It can be harder for students to create study groups and form relationships with their peers.

        Online classes also require either a computer or laptop and a reliable internet connection. Not all students have access to these types of resources, whether it is for financial or other reasons, and some students can be put at a disadvantage.

        Offering online classes certainly helps students who would otherwise not be able to attend classroom sessions. However, they fail to provide a genuine education with an emphasis on convenience rather than critical thinking. We need restructured online classes in which students can have a learning experience that will actually provide quality education.

解析：B。根据题干中的the author和students enrolled in online classes可定位至原文第二、三段。第二段提到，作者注册了一门在线课程，发现在线课程并不像宣传的那么好，只是一种满足课程要求的手段，在第三段中具体说到在线课程的不足，即学生缺乏学习欲望。B项与此内容相符，其中的unmotivated to learn对应第三段中的lack the desire to learn，故B项为正确答案。

 错项排除：A项利用第三段中出现的course material进行干扰，但原文是说学生并未真正参与到课程内容的学习中去，并没有说他们的课程资料是否容易获得，A项的access...easily主观臆断，故排除。C项干扰性较强，但这是宣传的（advertised）关于在线课程的好处，并不是作者的观点，故排除。D项利用第二段中的fulfil course requirements进行干扰，但原文是说在线课程只是（merely）一种满足课程要求的手段，并不是说很少有人（rarely）能满足课程要求，故D项排除。