(1)
A)One sixth of them are seriously polluted.
B)One third of them are seriously polluted.
C)Half of them are seriously polluted.
D)Most of them are seriously polluted. (2)
A)There was no garbage left to clean up.
B)There was more garbage than before and they had to work harder.
C)The river had become so clean that a lot of water-birds came back.
D)The river was much cleaner and they had to search for garbage. (3)
A)Most of them would be indifferent and keep on throwing garbage into the river.
B)They would join the students in changing the situation.
C)They would become more aware of the pollution problem.
D)They would think twice before they went swimming or fishing in the river.
原文：
Passage one
Last August, Susan and 42 other students got wet and dirty while removing
six tons of garbage from the river running across their city. They cleaned
up the river as part of a week-long environmental camp. Like one in three
American rivers, this river is so polluted that it's unsafe for swimming
and fishing, still, Susan, who has just completed her third summer on the
river clean-up ,scene has changed in this river." Since we started three
years ago ,the river is getting a lot cleaner", she says. Environmental
scientists praised the teenagers for removing garbage that can harm wild
life. Water birds, for example, can choke on plastic bottle rings and get
cut by scrap metal. Three years ago, when the clean-up started, garbage
was everywhere, but this year, the teenagers had to hunt for garbage. They
turn the clean-up into a competition to see who could find the most
garbage and unload their boats fastest. By the end of the six hour shift,
they have removed enough garbage to fill more than two large trucks."
Seeing all their garbage in the river makes people begin to care about
environmental issues," Susan says. She hopes that when others read that
she and her peers care enough to clean it up, maybe they will think twice
before they throw garbage in the river.
Questions 11-13 are based on the passage you have just heard.
11.What does the passage tell us about American rivers?
12.What did the students find when they came to the river this year?
13.What is the expected reaction of the local people to the students'
efforts?