英语听力精选进阶版 13653

（单词翻译）

Frankincense under threat, says study

Vocabulary

resin

sticky substance that runs inside the trunk of trees

drylands

areas with a small amount of moisture

struggling to sustain itself

having difficulty in keeping alive

monitored

watched carefully

to model the changing population

to make a projection of the number of specimens in the future

declining

reducing

livestock

farm animals

pushed out 

forced out of the area

safeguard

protect

traded

bought and sold