Xuèyè zài tǐnèi bùduàn xúnhuán.
Blood circulates continuously in the body.
Zhè shì yī gè èxìng xúnhuán.
This is a vicious cycle.
Wǒmen yào fāzhǎn xúnhuán jīngjì.
We need to develop a circular economy.
Sì jì xúnhuán, zhōu ér fù shǐ.
The four seasons cycle, repeating endlessly.