gōng kē : huán jìng kē xué > huán jìng yǔ 'ān quán lèi
mùlù
yīngwénjièshì
  1. n.:  environments and securities
fēnlèixiángqíng
<span title=张>zhāng</span> <span title=开>kāi</span> huán jìng gōng chéng ān quán gōng chéng huán jìng gōng chéng yǔ kē xué