VOA慢速英语:Great Barrier Reef Choking on Pollutants

短语讲解：

1. Reefs are the hard skeletons left at the bottom of the sea by small marine creatures called polyps.

at the bottom of 在…的底部
例句：You sound like you're at the bottom of a well.
听起来你象是在一个井底一样.

2. Farmers’ say they are going to use more sustainable practices as soon as possible.

as soon as possible 及早; 尽早，尽快
例句：So call me as soon as possible.
请尽快给我回复。