In recent years, more and more students have studied online. In an online course, learners watch recorded lessons, join live video classes and send their homework through a website. The biggest advantage is flexibility. A student can study at night or on a weekend, and someone who lives far from a university can still take a course. Online learning is often cheaper too, since there is no need to pay for travel or a room in the city. However, it has disadvantages. Some students find it hard to stay motivated without a teacher in the room, and others do not have a quiet place or a reliable internet connection at home. Many schools now combine the two approaches, with some lessons online and others in a classroom. This mixed method tries to give students the advantages of both.

Question: What is the main idea of the passage?