Darkness falls quickly in the tropics.

在热带地区夜幕降临迅速。

Night descends quickly in the tropics.

热带地区黑夜来得快。

In the tropics plants grow to huge proportions.

在热带，植物长得很高大。

The disease is thought to have originated in the tropics.

这种疾病据说起源于热带地区。

Being in the tropics meant that insects formed a large part of our life.

身处热带地区意味着昆虫成了我们生活的一大部分。