题目

Mac was cycling along a road in Canada’s Yukon, halfway through a 2,750-mile bike tour to Prudhoe Bay, Alaska. He was carrying a 30-pound camping bag, __41__ he wasn’t moving very fast. Suddenly, he heard loud breathing behind him. “Man, that’s a big dog!” he thought. He looked to the side, but to his great __42__, he saw that it wasn’t a dog, but a wolf, running hard to __43__ him. Mac’s heart jumped. He reached for the __44__ from his bag. With one hand on the handlebar, he __45__ the spray. A bright red cloud covered the wolf __46__, and it fell back, shaking its head. B欲鉴别石灰水、稀盐酸、蒸馏水三瓶失去标签的无色液体，提供的试剂有：①纯碱溶液 ②紫色石蕊溶液 ③酚酞溶液。只用一种试剂可将它们鉴别出来的是( )A. 只有①B. 只有②C. ①或②D. ①或②或③