题目

函数f（x）=x+1，x∈{﹣1，1，2}的值域是（ ） A．0，2，3  B．0≤y≤3  C．{0，2，3}    D．[0，3] 答案：C【考点】函数的值域． 【专题】计算题． 【分析】将定义域内的每一个元素的函数值逐一求出，再根据值域中元素的性质求出所求． 【解答】解：∵f（x）=x+1，x∈{﹣1，1，2} ∴当x=﹣1时，f（﹣1）=0 当x=1时，f（1）=2 当x=2时，f（2）=3 ∴函数f（x）=x+1，x∈{﹣1，1，2}的值域是{0，2，3} 故选C 【点评】本The True Story of Treasure Island It was always thought that Treasure Island was the product of Robert Louis Stevenson’s imagination. ___1___，recent research has found the true story of this exciting work. Stevenson, a Scotsman, had lived 　 2 　for many years in 1881 he returned to Scotland for a 　3 . With him were his American wife Fanny and his son　 4　 　. Each morning Stevenson would take them out for a long 　 5 　over the hills. They had been 6 this for several days before the weather suddenly took a turn for the worse, Kept indoors by the heavy rain. Lloyd felt the days　 7 　. To keep the boy happy Robert asked the boy to do some 　8 . One morning, the boy came to Robert with a beautiful map of an island. Robert 9 that the boy had drawn a large cross in the middle of 　10 . “What’s that?” he asked “That’s the 　11　 treasure “said the boy Robert suddenly 12 something of an adventure story in the boy’s　 13 While the rain was pouring, Robert sat down by the fire to write a story. He would make the　 　14 a twelve-year-old boy just like Lloyd. But who would he the pirate（海盗）? Robert had a good friend named Henley, who walked around with the 　15 of a wooden leg. Robert had always wanted to 　16　 such a man in a story 17 　Long John Silver the pirate with a wooden leg, was 　18　 . So thanks to a 　19 　.September in Scotland a friend with a wooden leg and the imagination of a twelve-year-old boy we have one of the greatest 　20 　stories in the English language. 1．A．However B．Therefore 　 C．Besides D．Finally 2．A．alone　 B．next door 　　　 C．at home D．abroad 3．A．meeting B．story　 　　　 C．holiday D．jib 4．A．Lloyd　 B．Robert 　 C．Henley　 D．John 5．A．talk 　 B．rest　 　　　 C．walk 　 D．game 6．A．attempting B．missing 　 C．planning D．enjoying 7．A．quiet　 　 B．dull　 　 　　C．busy 　 D．cold 8．A．cleaning B．writing 　 C．drawing D．exercising 9．A．doubted B．noticed 　 C．decided D．recognized 10．A．the sea B．the house 　 C．Scotland D．the island 11．A．forgotten B．buried 　 C．discovered D．unexpected 12．A．saw 　 B．drew　　　 C．made 　 D．learned 13．A．book　 B．reply　 　　　 C．picture 　 D．mind 14．A．star　 　 B．hero　 　　　 C．writer　 　 D．child 15．A．help　 　 B．problem 　 C．use 　 D．bottom 16．A．praise B．produce 　 C．include D．accept 17．A．Yet 　 B．Also　 　　　 C．But 　 D．Thus 18．A．read　 　 B．born　 　　　 C．hired　 　 D．written 19．A．rainy 　 B．sunny　 　 C．cool 　 D．windy 20．A．news　 　 B．love　 　　　 C．real-life　 D．adventure