Angela Weiss/AFP/Getty Images Kids across America are putting on masks and backpacks and heading back to school this spring as the country continues its hopeful but fragile march toward recovery from the Covid-19 pandemic. As welcome as these unusual first days of school are for many students — and parents who were thrust into the role of amateur educators this year — they come with a lot of uncertainty. Many school districts are still operating on a hybrid model, with each student attending school in person only part time; a few remain entirely remote. We still don’t know when children will be able to be vaccinated. And a rise in cases and the spread of variants has cast the next few months into doubt. A lot of families are wondering: What will happen in the fall?