说明文写作：保护脆弱世界 — 英语填空题
题目
在以 Protecting Our Delicate World 为题的说明文中，第二段围绕人类活动对自然的破坏展开，请补全主题句：Human activities, such as cutting down forests and pouring waste into rivers, have ___ (严重地) damaged the environment. Therefore, it is high time that we ___ (take) action to protect our delicate world.