What is the meaning of the allusion lisa was nostalgic about the halcyon days of summer?

Kasen just completed his second year of college in education. he is not sure if this is the best career choice for him. he wants to get some work experience, and so he takes a leave of absence from school. which job in education would he most likely be qualified for without a completed bachelor’s degree? preschool teacher kindergarten teacher special education teacher postsecondary teacher