1·The mightiest are native to North America, but big trees grow all over the globe, from the tropics to the boreal forests of the high latitudes.
最高大的树原产于北美，但大树遍布全球——从热带到高纬度的北方森林。
2·In the tropics, the valleys appear to be more favorable because they are less prone to dry out, they have less frost, and they have deeper soils.
在热带地区中，山谷似乎更有利于树木生长，因为山谷更加不容易干涸、较少结霜，并且拥有更深的土壤。
3·Old trees that don't grow in the tropics grow seasonally, and they grow faster early in the year in the springtime than they do later in the year.
所有不生长在热带地区的老树都是季节性生长的，它们在每年初的春天时节长得较快，之后几年长得较慢。
4·The US National Center for Atmospheric Ressearch has already suggested that the proposal to inject ulphur into the atmosphere might affect rainfall patterns across the tropics and the Southern Ocean.
美国国家大气研究中心已经表示，向大气中注入硫的提议可能会影响整个热带和南大洋的降雨模式。
5·The US National Center for Atmospheric Research has already suggested that the proposal to inject sulphur into the atmosphere might affect rainfall patterns across the tropics and the Southern Ocean.
美国国家大气研究中心已经表示，向大气中注入硫的提议可能会影响整个热带和南大洋的降雨模式。