求证：不交于同一个点的四条直线两两相交，则这四条直线共面．
（1）若三直线l1、l2、l3交于一点A（如图），
则由点A与l4确定一个平面α
A∈α，B∈α，AB?α，l1?α，
同理可得l2?α．、l3?α，
∴l1、l2、l3、l4四点共面．
（2）若四直线无三线共点，设两直线交于一点，
如l1∩l2=A．，则l1、l2确定一个面α，则B∈α，C∈α?l3?α．
同理l4?α?四线共面．
第二节 信息匹配(共5小题；每小题2分，满分10分) 阅读下列应用文及相关信息，并按照要求匹配信息。请在答题卡上将对应题号的相应选项字母涂黑。 以下是一些图书的信息： A History has forgotten the shocking cruelties unleashed on the animals of Britain in centuries past. But their grim legacy remains in the language we speak. The rescued dogs, cats, rabbits and horses who live with so many of us today ultimately owe their survival to British reformers, writes Kathryn Shevelow in For the Love of Animals: The Rise of the Animal Protection Movement. These men and women, she writes, “forced the law for the first time to become responsive to the plight of animals.” B Dewey: The Small-Town Library Cat Who Touched the World By Vicki Myron with Bret Witter Grand Central Publishing 277 pp. $19.99 C I once interviewed a little girl who lived in a run-down trailer. Her family faced every kind of economic and social deprivation you can imagine, yet she was bright and cheerful with a cherished plan for her adult years. “I’m going to have a job that has to do with rescuing animals,” she confided in me. How many of us there must be – we who dream of saving the animals! That means that, potentially, there’s a huge audience for Benjamin Mee’s real-life animal-rescue story We Bought a Zoo. D "The heartwarming and true story of Wesley, a barn owl, and his human friend and biographer, Stacey O'Brien. Ms. O'Brien, a biologist, rescued Wesley as an injured owlet, and this wonderful book reveals insights into owl behavior gained through her 19 years living with Wesley. Her words say it best: "He was my teacher, my companion, my child, my playmate, my reminder of God."" E A former Wall Street Journal nature columnist and author of the best-selling “Red-Tails in Love,” Winn once again tackles urban wildlife with gusto. Winn’s engaging tales begin with her love of bird watching, but as she trains her binoculars she discovers that she’s not alone in her urban oasis. Through her curiosity for nature, she finds other like-minded people – citizen scientists – whom she befriends. Together they gather at night to identify moths’ wing patterns and watch with fascination the mysterious mating rituals between two slugs hanging from a tree limb. F It should surprise no one that the best way to preserve nature is to ensure that all of its parts are in place. But the reality is that humans have long been waging a war against large carnivores – lions and tigers and bears, to name but a few. The result, says author William Stolzenburg in this absorbing and delightful work of natural history, is that we have thrown the balance of nature out of whack. The science he presents is not all new, but the scientific perspective Stolzenburg reflects will be fresh and illuminating to many readers. 以下是一些图书的封面。请匹配图书的封面与它们所对应的信息。 61 62 63
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