If you want to know what school was like in 2020, let me tell you about one moment that has stuck with me for months. One Thursday morning in October, my daughter, an eighth-grader, spent her “homeroom” period performing a school lockdown drill. She was, of course, in her own house, like all her classmates. The students watched a video on their computers about lockdown procedures, then practiced hiding under desks. And so it happened that in this, the most absurd and bewildering academic year of her life, my eighth-grader tucked herself under the table in her bedroom, to prepare for the possibility that someone might try to shoot her, someday later, at her school.