States are reopening. Parks are crowded. Restaurants are filling, again, with diners. But is this dangerous? Six months into the pandemic, we reflect on what we’ve learned about the virus — and ask how that knowledge should chart the course forward. Guest: Donald G. McNeil Jr., a science and health reporter for The New York Times. For more information on today’s episode, visit nytimes.com/thedaily  Background reading: As New York businesses reopened, Gov. Andrew Cuomo warned that a second wave of infections was almost inevitable if residents did not abide by social-distancing rules. “It will come,” he said. “And once it comes, it’s too late.” Restrictions are easing across the United States, but Arizona, Florida and Texas are reporting their highest case numbers yet. As of Saturday, coronavirus cases were climbing in 22 states.