CONCORD — Gov. Chris Sununu said Thursday by April 19 all K-12 schools must return to full-time, in-person learning five days a week. About 60 percent of schools are already doing this. Many schools had plans to return to five days a week or close to it on May 3, but this will speed up the timeline or changes plans entirely in some cases. “We know one, schools can reopen safely, and second, all teachers and staff that want the vaccine will have received their second dose,” Sununu said. “Third, we’re providing additional time for schools and families to plan, and fourth, we all know we need to get our kids back into school.”