A．Schools use private detection services.
B．Teachers discuss essay topics with their students.
C．Teachers ask students to turn in early drafts of papers.
D．Universities stop students from buying essays.

A．Those that are involved in a specific field.
B．Those that are very difficult and urgent.
C．Those that need cooperation of two writers.
D．Those whose writers are from abroad.

A．Their work can only be used as a model.
B．Most of their writers are poorly paid,
C．Most writers have doctorate degrees.
D．Students may handle the paper as they wish.