1 sentence

1. 你的心脏有四个瓣膜，可以保持血液流向正确的方向。

   nǐ de xīn​zàng yǒu sì ge bàn​mó, kě​yǐ bǎo​chí xuè​yè liú​xiàng zhèng​què de fāng​xiàng.

   Your heart has 4 valves that keep blood flowing in the right direction.

   Source: CCMatrix