S 回归线 either of the two circles round the earth,one about 23 degrees south of the equator
P 热带，热带地方 the parts of the world between these two lines
词汇搭配
介词+～
in the tropics 在热带地区
～+介词
the T- of Cancer〔Capricorn〕 北〔南〕回归线
句型例句
Darkness falls quickly in the tropics.热带地区天黑得很快。
I went to the tropics for the first time last year.我去年第一次去了热带地区。
The coconut is particular to the tropics.椰子是热带地区的特产。
