A recent survey found students aren’t nearly as prepared for class as professors expect them to be.The National Survey of Student Engagement surveyed 380,000 freshman and seniors at 722 four-year colleges this spring.Students reported spending only 3 1/2 hours a week preparing for each class — only half the time professors expect.About 20 percent of students surveyed said they come to class without completing reading or assignments, but 59 percent of seniors and 55 percent of freshman said they have to work harder to meet a professor’s standards.——Contact Leslie Presnall at [email protected]