Complex sentence: In 1961, a letter was sent to all of the Chinese medium high schools demanding them to convert teaching of all subjects into the English Language before 1 April 1962, failing to do so the schools would not be given any allocations from the government.
Split into simpler sentences: In 1961, a letter was sent to all of the Chinese-medium high schools demanding them to convert teaching of all subjects into English before 1 April 1962. Failing to do so, the schools would not be given any allocations from the government.