In Australia there is a famous island called Fraser Island. A great many visitors come here for holidays every year. In fact, it is the largest sand island in the world. Though the island is a popular place of interest, there is no airport on the island. Planes arrive and leave from the long beach along the east coast.
Every year, visitors come to enjoy the island's natural beauty. People always like camping and hiking there. Unluckily, visitors caused many problems. They caused the extinction (灭绝) of animals. And they also caused the pollution of lakes. So it is time to protect the environment of the island. People set up some rules. For example, visitors are not allowed to use motorboats (摩托艇) or go fishing in the lakes. Most importantly, they mustn't leave any rubbish.
ato let somebody do something, let (something)be done
rthings or material of no use that will be thrown away
They threw rubbish everywhere, and the lakes were seriously polluted.
They threw rubbishand, and the lakes were seriously polluted.