题目

完形填空。阅读下面短文，掌握其大意，从每题所给的A、B、C、D四个选项中，选出最佳选项 Although it was autumn, the snow was already beginning to fall in Tibet (西藏). Our legs were so heavy and cold that 1 felt like big pieces of ice. Have you 2 seen snowmen ride bicycles? That's what we looked like! Along the way children who were 3 long wool coats stopped to look at us. In the late 4 we found it was so cold that our water bottles froze (结冰). However, the lakes 5 like glass in the setting sun and looked wonderful. Wang Wei rode in front of me as usual.英国博物学家达尔文进化理论的核心是（　　）A．生存斗争B．自然选择C．遗传变异