These conditions are most prevalent in tropical regions; however population migration has spread theThese conditions are most prevalent in tropical regions; however population migration has spread the
这些病症在热带地区最为普遍；不过，随着人口迁移，这些疾病已传播到大多数国家。
The virus is endemic in tropical regions of Africa and the Americas.The virus is endemic in tropical regions of Africa and the Americas.
该病毒在非洲和美洲的热带地区呈地方性流行。
a small, low island in tropical regions, made of rock, sand, or coral (= a hard substance formed ina small, low island in tropical regions, made of rock, sand, or coral (= a hard substance formed in
There are a number of different islands, or keys, here.
the time of year when large quantities of rain fall in some tropical regions of the world:the time of year when large quantities of rain fall in some tropical regions of the world:
During the wet season in the summer, the lake is four times as big as it is now.
the time of year when a lot of rain falls in some tropical regions of the world:the time of year when a lot of rain falls in some tropical regions of the world:
During the rainy season, parts of the road lie under several feet of floodwater.
