66-year-old Dai once worked as a boat tracker along the Yangtze River. "It was something that required brute strength,but not that alone, "Dai said at his home in Xialong village, which sits at the entrance to Wuxia Gorge, one of the famous Three Gorges in Southwest China. "You needed a lot of skills to do what we did." When outboard motors became available in the 1980's,boat trackers became a thing of the past. Today, they are seen only occasionally along the river during festivals and cultural events. However, Dai can still remember a time when being pulled by tracker along the Yangtze was the only way for people to travel from village to village in the mountainous Wushan county. Due to the area's rich mining resources,his services were vital for companies that wanted to ship their goods. "I was 15 or 16 when I started", said the retiree,explaining that his father also worked as a tracker. "He died in 1964, when I was a teenager. I can't even remember us tracking together, but we did. It was so long ago." Dai said that boats crews worked in teams with a first, second and third master. The first master was the most essential because he sat in the boat and steered   it along the safest route. "It was a key role. He had to guide the boat past jagged rocks and whirlpools," he said, adding that first masters were often the most experienced boatmen and the most familiar with the Yangtzer River. "My tracker days were dangerous," Dai said. "If the boat got caught in a whirlpool, it could have swallowed the boat and all the trackers down with it. The same thing would have happened if the halter   broke." Dai's days as a tracker finally came to an end when his family invested in a motorboat in the early 1980s. He successfully applied for a license from Wushan shortly after. We can conclude from the passage that   _
both people and goods were once pulled by trackers along the Yangtze actually Dai didn't track with his father at all the most experienced boatmen were sure to be the first masters if the boat was caught in a whirlpool, a11 the trackers had no chance to survive
Question: 66-year-old Dai once worked as a boat tracker along the Yangtze River. "It was something that required brute strength,but not that alone, "Dai said at his home in Xialong village, which sits at the entrance to Wuxia Gorge, one of the famous Three Gorges in Southwest China. "You needed a lot of skills to do what we did." When outboard motors became available in the 1980's,boat trackers became a thing of the past. Today, they are seen only occasionally along the river during festivals and cultural events. However, Dai can still remember a time when being pulled by tracker along the Yangtze was the only way for people to travel from village to village in the mountainous Wushan county. Due to the area's rich mining resources,his services were vital for companies that wanted to ship their goods. "I was 15 or 16 when I started", said the retiree,explaining that his father also worked as a tracker. "He died in 1964, when I was a teenager. I can't even remember us tracking together, but we did. It was so long ago." Dai said that boats crews worked in teams with a first, second and third master. The first master was the most essential because he sat in the boat and steered   it along the safest route. "It was a key role. He had to guide the boat past jagged rocks and whirlpools," he said, adding that first masters were often the most experienced boatmen and the most familiar with the Yangtzer River. "My tracker days were dangerous," Dai said. "If the boat got caught in a whirlpool, it could have swallowed the boat and all the trackers down with it. The same thing would have happened if the halter   broke." Dai's days as a tracker finally came to an end when his family invested in a motorboat in the early 1980s. He successfully applied for a license from Wushan shortly after. We can conclude from the passage that   _
A. both people and goods were once pulled by trackers along the Yangtze
B. actually Dai didn't track with his father at all
C. the most experienced boatmen were sure to be the first masters
D. if the boat was caught in a whirlpool, a11 the trackers had no chance to survive
Answer: