Determined to reopen America’s schools despite coronavirus worries, President Donald Trump threatened Wednesday to hold back federal money if school districts don’t bring their students back in the fall. He complained that his own public health officials’ safety guidelines are impractical and too expensive. Shortly afterward, Vice President Mike Pence announced that the Centers for Disease Control and Prevention would be issuing new guidance next week “that will give all new tools to our schools.” The recommendations will keep students safe, he said, but “the president said today we just don’t want the guidance to be too tough. ”Despite Trump’s increased pressure on state and local officials, New York City announced that most of its students would return to classrooms only two or three days a week and would learn online in between. “Most schools will not be able to have all their kids in school at the same time,” said Mayor Bill de Blasio.