题目

已知a是函数f(x)＝2x－的零点，若0<x0<a，则f(x0)的值满足( ) (A)f(x0)＝0             (B)f(x0)>0 (C)f(x0)<0              (D)f(x0)的符号不能确定 答案：C.由指数函数、对数函数的单调性可知函数f(x)是定义在(0， ＋∞)上的增函数，又a是f(x)的零点，∴f(a)＝0，又0<x0<a，∴f(x0)＜0，故选C. 短文改错(Proof-reading) 　　此题要求改正所给短文中的错误。对标有题号的每一行做出判断：如无错误，在该行右边横线上画一个勾(√)如有错误(每行只有一个错误)，则按下列情况改正： 　　此行多一个词：把多余的词用斜线(\)划掉，在该行右边横线上写出该词，并也用斜线划掉。 　　此行缺一个词：在缺词处加下个漏字符号(∧)，在该行右边横线上写出该加的词。 　　此行错一个词：在错的词下划一横线，在该行右边横线上写出改正后的词。 　　注意：原行没有错的不要改。 　　Nelson Mandela's greatest pleasure, his most private moment, is watching the sun set with the music of Handel or Tchaikovsky playing． 　 And his fellow prisoners, concerts were organized 1．________ when possible, especially at Christmas time．Now they 2．________ would sing．Nelson Mandela finds music very uplifting (情绪高涨的)， 　 and took an interest not only in European 3．________ classical music but also about African choral music and 4．________ many talents in South African music．But one voice stands 　 out after all that is of Paul Robeson, whom he describes 5．________ for our hero． 6．________ He has formed some health habits in the years in 7．________ prison：the eating habit of an athlete began in 1940 s, 8．________ as did the early morning exercise．Still today Nelson 　 Mandela is up by 4∶30 am, irrespective(不考虑)of 　 what late he has worked the previous evening．By 5 am 9．________ he has begun his exercise that lasts at least an hour． 　 Breakfast is by 6∶30, when the day's newspapers are 　 reading．The day's work has begun． 10．________