If you were to throw,say,a banana peel out of your car while driving along the motorway,that would be a completely harmless action,due to the fact that it's part of a fruit - right？Actually,no.A banana peel can take up to two years to be naturally processed,and with a third of motorists admitting to littering while driving,that's a whole lot of discarded banana peels.An orange peel and a cigarette butt has a similar biodegrading （生物降解）term to that of a banana peel,but tin cans last up to 100 years；and plastic bottles last forever,as do glass bottles.
Despite the fact that longer-lasting materials will serve to damage the environment and its animals for longer,we can't merely measure the severity of a certain type of rubbish by its lifetime.For example,despite having a fairly short length of biodegrading time,more than 120 tons of cigarette-related litter is discarded in the UK every day.
It's not a cheap habit either：to keep our streets clean annually costs UK taxpayers £500 million,and when you include our green spaces,that goes up to £1 billion.So,it's not surprising that if caught fly-tipping you could face a £20，000 fine or even jail time and,if you disposed of something dangerous,the court could give you five years to serve.Regardless of how severe these punishments might seem,however,among the reported cases only 2，000 were found guilty out of 825，000，so we still have some way to go in making sure people obey the rules.



What does the underlined word "discarded" in para 1 mean？ ______

A. Harmless.
B. Processed.
C. Thrown.
D. Long-lasting.

Which of the following has the longest biodegrading term？ ______

A. Glass bottles.
B. Tin cans.
C. Cigarette butts.
D. Banana peels.

What can be inferred from the passage？ ______

A. The severity of rubbish can be measured by its lifetime.
B. Quite a few people were found guilty of illegally littering.
C. Every year UK taxpayers spend £500 million keeping streets free of dirt.
D. Cigarette-related litter and peels can be ignored for their fairly short lifetime.

What is the purpose of the passage？ ______

A. To inform readers of different biodegrading terms.
B. To call for people not to litter illegally.
C. To encourage people to use fewer plastic bags.
D. To stress the importance of good behavior.