阅读理解。 One day, Bob took two of his friends into the mountains. They put up their tents (帐篷) and then rode off to a forest to see the trees growing. In the afternoon, when they were about ten kilometers from their camp (营地), it started to snow. More and more snow fell. Soon Bob could hardly see his hands before his face. He could not find the road. Bob knew there were two roads. One road went to the camp, and the other went to his house.But all was white snow. Everything was the same. How could he take his friends back to the camp? Bob had an idea. The horses! Let the horses take them back! But what would happen if the horses took the road to his house? That would be a trip of thirty-five kilometers in such cold weather! It was getting late. They rode on and on. At last the horses stopped. Where were they? None of them could tell. Bob looked around. What was that under the tree? It was one of their tents! 1. Bob and his two friends went to the forest to _____. [     ] A. build their camp B. find their way home C. enjoy the mountains in the snow D. watch the trees in the forest 2. They could not find their way back because _____. [     ] A. there was only one road to their camp B. they couldn't decide which of the two roads led to their tents C. there were no roads in the mountains at all D. everything was covered by the white snow 3. It is clear that they wanted the horses to take them to _____. [     ] A. John's house B. the camp C. the forest D. the mountains 4. The horses stopped because _____. [     ] A. it was getting late B. they were tired after running for a long way C. they knew that they had got to the camp D. they had seen John's house