Passage Two Questions 21 to 23 are based on the passage you have just heard.

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A．He taught his students how to pronounce the letters first.
B．He matched the letters with the sounds familiar to the learners.
C．He showed the learners how to combine the letters into simple words.
D．He taught his students how to pronounce the letters first. B) He matched the letters with the sounds familiar to the learners. C) He showed the learners how to combine the letters into simple words. D) He divided the letters into groups according to the way they are written.