Cambridge English Qualifications gave learners and teachers different curriculum and examination levels by starting with G6 Proficiency and B1 Preliminary in 1980, and in the 1990s, the addition of A2 key and C! advanced, providing another range of different cirriculum and examination levels.
Cambridge Assessment English exams, starting with C2 Proficiency in 1913, B2 First in 1939, and B1 Preliminary in 1980, gave learners and teachers different curriculum and examination levels. 
