This way of teaching frequently uses chants, mimicry and the practice of interactive safety guarding, an approach for fellow teachers' reference.

为此，我们在自由泳教学中，较多运用口诀、模仿和互助保护练习。 仅以此文供同仁们参考。

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In the United States, singers in the African-American church popularized the vocal practice, which dates to Gregorian chants and Indian ragas.

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