Alsten Chase has written a book about Yellowstone National Park. He is worried about the damage the fires can do to the park. He is also concerned(关心) about the park rules.
These rules say that nature should decide what happens to the park. Alsten also writes that the elk herd(马鹿群) has grown too big. The elks walk on the riverbanks. They eat the new grass and roots of baby trees. The beavers (河狸) need the trees to build dams.
The dams raise the water levels. Higher water levels put more water into the soil. Moist soil helps plants grow faster. The plants offer homes and food to other animals.
Chase thinks that the park rules would work only in a park with natural settings. He believes that Yellowstone has had an artificial setting for a long time. The native people left. The wolves were taken away and other animals were removed．The areas of land were fenced off and other animals added．He thinks the park rules that let herds grow too big and the fires burn are hurting the nature of the park.
The park manager thinks the rules are good and that the park will be fine. Chase thinks the way the people run the park should be changed.
In Chase’s opinion, too many elks in the park will ___.

A．cause great fires	B．break the balance of nature
C．destroy the dams	D．do no damage at all

Chase thinks that the park is ____.

A．no longer in a natural state	B．still in a natural stat
C．well protected	D．well managed

After the book by Alsten Chase is published, the park will probably ___.

A．be quickly changed	B．be completely replaced
C．no longer work	D．continue to work