A. The Earth. B. The sun. C. God.

20. Why did Copernicus publish his theory while he was dying?

A. He wasn't sure of his theory until then.

B. He was afraid of being punished.

C. His friends told him not to publish it.

第二部分 阅读理解(共两节，满分35分)

第一节 (共10小题；每小题2.5分，满分25分)

　　阅读下列短文，从每题所给的A、B、C和D四个选项中，选出最佳选项。

　　Reducing the Risk of Bear Encounters

　　Be alert. Watch for tracks, droppings, diggings, and other bear signs. If you see a cub, move away immediately - you can be certain the mother is nearby.

　　Make noise. Typically, bears avoid humans. You can make this easier for them by making noise when hiking in the backcountry - talk with your companions, sing a song, whistle.

　　Watch for carcasses（兽类的尸体） and stay away from them. Report all dead animals found near a trail or campsite to a park employee. If you smell rotten meat, leave the area immediately. Never approach or camp near a carcass. A bear may be out of sight, guarding its food.

　　Avoid carrying items with strong smell. Bears are attracted by smells of food and other items with strong smell. Leave food like bacon, tuna, ham, and scented personal products at home. Bears have a great sense of smell and can detect smells miles away. We recommend using dry, sealed foods; they are lighter and less fragrant.

　　Keep a clean camp and store food items securely. For the protection of bears, park visitors and employees, it is very important that bears do not gain access to human food. Never eat or store food in your tent. Get rid of food left after a meal properly (pack it in, pack it out) and don't leave food, dishes, or stoves unattended.

　　In areas where bears are known to be active, keep your sleeping area away from your cooking and food-storage area. Store food, garbage, and other items in vehicles or in bear-proof containers. If these are unavailable, hang food and other items with strong smell in a strong bag as high as possible in a tree.

21. What does the underlined word "cub" mean in paragraph 1?

A. a place where a bear lives B. a young bear

C. a male bear D. a bear's paw

22. To avoid meeting with bears, we should_____.