单项选择题
A．using various telescopes B．based on Aristotle’s beliefs C．through observations and reasoning D．under the encouragement of his friends
A．an average B．a total C．an exam D．a number
A．how to hunt whales for their oil and meat B．the hard and dangerous lives that whalers had to live C．the duties of each man on a whaling ship D．a man who was swallowed by a whale and lived