Complex sentence: German in the 19th and early 20th century was an important language of science and technology, but it has now largely lost that role, and is no longer widely studied in Great Britain except at the A-level in secondary schools.
Split into simpler sentences: German in the 19th and early 20th century was an important language of science and technology, but it has now largely lost that role. German is no longer widely studied in Great Britain except at the A-level in secondary schools.