half the size of the United States... 有半个美国那么大

8. and the rivers of fire are gradually subsiding.
   熔岩河逐渐平息
9. In their wake,
   因此
10. cooling lava covers an area
    冷却的熔岩覆盖了一片区域
11. half the size of the United States...
    有半个美国那么大
12. ...in a crust up to three kilometers deep.
    表层厚达三千米
13. Volcanic gases have caused global temperatures to soar.
    火山气体导致全球气温飙升
14. Forests and reefs
    森林和珊瑚礁

来自《我们星球上的生命 第一季 第四集 Life on Our Planet S01E04 冷血动物》第 11 行