单选题 There were still a few surprises, as a squeal here and there in the dark announced, but we did learn to "see with our feet"—lessons in trail Braille.
【正确答案】 B
【答案解析】解析：A．divergence分歧，偏斜；B．scream尖叫声，喊叫声；C．gradation分等级，阶级；D．strand海滨，绳。