A student listens to a lecture on a laptop at home during a remote learning class in Princeton, Ill., on Sept. 11, 2020. (Daniel Acker/Bloomberg News)

Millions of students across the country are once again going to school from home, as they did last spring when the novel coronavirus arrived in the United States.

Experiences with online learning this year have sparked concerns that many students are falling behind academically — not only because virtual school can’t replicate what happens in a brick-and-mortar school but also because many students are struggling with the technology to access online classes.