xué / xí / wài / yǔ / shí / fēn / qīng / zhuó / yīn / hé / qīng / yīn / fēi / cháng / zhòng / yào

学习外语时，分清浊音和清音非常重要。

When learning a foreign language, it is very important to distinguish voiced sounds from voiceless sounds.