Je was op zoek naar: 我要谈谈四个核心问题所面临的... (Chinees (Vereenvoudigd) - Engels)

现在，我要谈谈四个核心问题所面临的挑战。
i should now like to refer to the challenges that exist in the four core issues.

(c) 臭氧研究活动所面临的挑战；
(c) challenges facing ozone research activities;