FRANKFORD, Del. — American schools are scrambling to provide services to the large number of children and teenagers who crossed the border alone in recent months. Officials were caught off guard by about 70 new students mostly from Guatemala — part of the wave crossing the border — enrolling last year, mostly at Sussex Central High School. The students are eager but face barriers. Some can barely read or write in their native language. Donald Hattier, a school board member, said advance warning would have helped with planning. The federal government, he said, "just dropped this on us." He wonders...