，。
Trees give off oxygen and absorb carbon dioxide.
How to pronounce 二氧化碳
How to pronounce
in Mandarin Chinese
èr二yǎng氧huà化tàn碳
carbon dioxide CO2
HSK 6
Synthesized Mandarin audio · Vivian voice
èrFourth toneyǎngThird tonehuàFourth tonetànFourth tone
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，
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A syllable has a shape.
Tone marks show how pitch changes. Colors help you follow each syllable in the app.
ā First toneHigh and level
á Second toneRising
ǎ Third toneLow, then rising in isolation
à Fourth toneFalling
a Neutral toneShort and light
These are dictionary tones. In natural speech, tones can change with context. A third tone often stays low before another syllable.