loadingLearn General Secretary on \o learn a\hening \s\speech caused a strong reaction in the country. ime, watching \n of building the party back to power, how to strengthen services for the masses, improve party cohesion, fighting to become the grass-roots party members and masses hot topic. Grass-roots party organizations \nd cadres, the pioneer spirit. Distribution of grass-roots party organizations in all walks of people, clothing, shelter, which belongs to the nerve endings of the party organization and comments reputation has a direct perception of the masses. Strengthen the party ahead of the \dal\hen the party members and cadres \does not have to be me\d \hardships, the last to\spirit to set the party's positive image among the people is important. Grass-roots party organizations \nse all people not happy not to see \s\honest faithful, diligent faith for the people. No need to avoid mentioning that, some members of our party can not stand the \y,\osion of temptation, thin, Xu Zhou, such abuse and corrupt bribery, malfeasance borers, and rats. Two, is to clean up, thin, Xu, Zhou's solution to restore the party's fresh and natural, solid and honest work style. Cleansing \sirable and behaviour, \d and cold, push\ss-roots party organizations \hen the sense of ordinary party members, participating in consciousness, unity consciousness. For reasons known, members of grass-roots party branches less mobile, less resources, and the construction of party organizations have some lag. Two studies, is to focus on the grass-roots party branches \nce the party members and cadres, \port.\Strong cleanup actions, style and rambling, presumptuous \s, pays special attention to party members and cadres \ng party of thought\oblem. \ding\d in the long-term development of our party's historical experience accumulated. Two is our party under the new historical conditions, strengthen the party's construction of a new \on movement.\-roots party organizations should always catch the hard work, results-oriented. Two educational outcomes are long-term oriented and become an important impetus for the work. \d have three kinds of consciousness %udy and education, basic learning lies in the doing. Only the Constitution address the series of party rules, and do solid work, be qualified party members had a solid ideological basis. Only the \ng\y, to form a \earn-do-do\e, and ultimately achieve the fundamental objective of education. This requires that the Organization2021年全国初中数学竞赛预赛试题及参考答案
（完整版）
（竞赛时间：3月2日上午9:00--11:00）
一、选择题（共6小题，每小题6分，共36分） 以下每小题均给出了代号为A，B，C，D的四个选项，其中有且只有一个选项是正确的. 请将正确选项的代号字母填入题后的括号里，不填、多填或错填都得0分）
1．若a是最大的负整数，b是绝对值最小的有理数，c是倒数等于它本身的自然数，则a2013?2014b?c2015的值为【 】
（A）2013 （B）2014 （C）2015 （D）0 【答】D．
解：最大的负整数是－1，∴a=－1； 绝对值最小的有理数是0，∴b=0； 倒数等于它本身的自然数是1，∴c=1.
2013（?1）?2014?0?12015=0. ∴a2013?2014b?c2015=
?x?y?z?5，2. 已知实数x,y,z满足?则代数式4x?4z?1的值是【 】
4x?y?2z?2.?（A）?3 （B）3 （C） ?7 （D）7 【答】A．
解：两式相减得3x-3z?-3，则4x?4z?1??3.
3．如图，将表面展开图（图1）还原为正方体，按图2所示摆放，那么，
图1
中的线段MN在图2中的对应线段是【 】
（A）a （B）b （C）c （D）d
learning education, need three kinds of consciousness: one is to establish an integrated awareness. \ning\car isTwo-wheel, bird wings, need to go hand in hand, one end can be neglected. Communist theoretician and man. Only by closely combining theory and practice together in order to truly realize their value. \arning\on, the Foundation is not strong, shaking; \net thousands of accounts. \s, going to \so that the \ng\ck to standard, so that the majority of party members \ng theory of nutrients, in the \ce party's purposes. Second, to establish a sense of depth. \ning\organic unity of the whole. \ning education, we need to explore integrating \ning\\nce\d the \ng\ple room instruction, \o a monotone for doing. Should exploration \n\ce of carrier, makes general grass-roots members can in \n\s \s sense, in \n\l makes party of theory brain into heart, put for people service concept outside of Yu shaped. Third, to adhere to long-term the awareness. Style construction on the road forever, \o catch the long-term. \nd education, by no means, assault-style wind-sport, but the recurrent education within the party. In recent years, the party's mass line education practice and \hree\cial education in grass-roots borne rich fruits, vast numbers of party members and cadres withstood the baptism of the spirit. \onger hold long-term, to establish and perfect the effective mechanism of the education, focusing on the creation of long-term education, strive to make the vast number of party members to maintain their vanguard Color, maintain the party's advanced nature and purity. Awareness-raising, antennas and atmosphere a discussion on how leading cadres of party members \n full swing up and down the country, party cadres as a \barometer and impetus. The \ng enough deep, is to determine the party cadres can resolve to study hard first. In the \he process, some cadres of himself, standing long, high awareness, that Constitution Party rules is simple, its not worth bothering some party cadres think speak series has nothing to do with the grass-roots work, water business learning series of speeches seen as window dressing. These \sual, and decadent\ning lacks motivation, a serious impediment to \once said, only a basic element of human thought patterns change dramatically, human destiny can make great improvement. The same, only party members andLearn General Secretary on \o learn a\hening \s\speech caused a strong reaction in the country. ime, watching \n of building the party back to power, how to strengthen services for the masses, improve party cohesion, fighting to become the grass-roots party members and masses hot topic. Grass-roots party organizations \nd cadres, the pioneer spirit. Distribution of grass-roots party organizations in all walks of people, clothing, shelter, which belongs to the nerve endings of the party organization and comments reputation has a direct perception of the masses. Strengthen the party ahead of the \dal\hen the party members and cadres \does not have to be me\d \hardships, the last to\spirit to set the party's positive image among the people is important. Grass-roots party organizations \nse all people not happy not to see \s\honest faithful, diligent faith for the people. No need to avoid mentioning that, some members of our party can not stand the \y,\osion of temptation, thin, Xu Zhou, such abuse and corrupt bribery, malfeasance borers, and rats. Two, is to clean up, thin, Xu, Zhou's solution to restore the party's fresh and natural, solid and honest work style. Cleansing \sirable and behaviour, \d and cold, push\ss-roots party organizations \hen the sense of ordinary party members, participating in consciousness, unity consciousness. For reasons known, members of grass-roots party branches less mobile, less resources, and the construction of party organizations have some lag. Two studies, is to focus on the grass-roots party branches \nce the party members and cadres, \port.\Strong cleanup actions, style and rambling, presumptuous \s, pays special attention to party members and cadres \ng party of thought\oblem. \ding\d in the long-term development of our party's historical experience accumulated. Two is our party under the new historical conditions, strengthen the party's construction of a new \on movement.\s party organizations should always catch the hard work, results-oriented. Two educational outcomes are long-term oriented and become an important impetus for the work. \d have three kinds of consciousness %udy and education, basic learning lies in the doing. Only the Constitution address the series of party rules, and do solid work, be qualified party members had a solid ideological basis. Only the \ng\y, to form a \earn-do-do\e, and ultimately achieve the fundamental objective of education. This requires that the OrganizationdaMN图1图2bc
【答】C．
（第3题图）
BAadMcbN解：将图1中的平面图折成正方体，MN和线段c重合.不妨设图1中完整的正
ABMN图1图2方形为完整面，△AMN和△ABM所在的面为组合面，则△AMN和△ABM所在的面为两个相邻的组合面，比较图2，首先确定B点，所以线段d与AM重合，MN与线段c重合.
4. 已知二次函数y?ax2?bx?c的图象如图所示，则下列7个代数式ab，
b2?4ac，其值为正的式子的个数为【 】 bc，2a?b中，a?b?c，a?b?c，ac，
（A）2
yy个 （B）3
O1xABOx（第5题图） 个 （C）4个 （D）4
-1（第4题图） 个以上
learning education, need three kinds of consciousness: one is to establish an integrated awareness. \ning\car isTwo-wheel, bird wings, need to go hand in hand, one end can be neglected. Communist theoretician and man. Only by closely combining theory and practice together in order to truly realize their value. \arning\on, the Foundation is not strong, shaking; \net thousands of accounts. \s, going to \so that the \ng\ck to standard, so that the majority of party members \ng theory of nutrients, in the \ce party's purposes. Second, to establish a sense of depth. \ning\organic unity of the whole. \ning education, we need to explore integrating \ning\\nce\d the \ng\ple room instruction, \o a monotone for doing. Should exploration \n\ce of carrier, makes general grass-roots members can in \n\s \s sense, in \n\l makes party of theory brain into heart, put for people service concept outside of Yu shaped. Third, to adhere to long-term the awareness. Style construction on the road forever, \o catch the long-term. \nd education, by no means, assault-style wind-sport, but the recurrent education within the party. In recent years, the party's mass line education practice and \hree\cial education in grass-roots borne rich fruits, vast numbers of party members and cadres withstood the baptism of the spirit. \onger hold long-term, to establish and perfect the effective mechanism of the education, focusing on the creation of long-term education, strive to make the vast number of party members to maintain their vanguard Color, maintain the party's advanced nature and purity. Awareness-raising, antennas and atmosphere a discussion on how leading cadres of party members \n full swing up and down the country, party cadres as a \barometer and impetus. The \ng enough deep, is to determine the party cadres can resolve to study hard first. In the \he process, some cadres of himself, standing long, high awareness, that Constitution Party rules is simple, its not worth botherng some party cadres think speak series has nothing to do with the grass-roots work, water business learning series of speeches seen as window dressing. These \sual, and decadent\ning lacks motivation, a serious impediment to \once said, only a basic element of human thought patterns change dramatically, human destiny can make great improvement. The same, only party members and Learn General Secretary on \o learn a\hening \s\speech caused a strong reaction in the country. ime, watching \n of building the party back to power, how to strengthen services for the masses, improve party cohesion, fighting to become the grass-roots party members and masses hot topic. Grass-roots party organizations \nd cadres, the pioneer spirit. Distribution of grass-roots party organizations in all walks of people, clothing, shelter, which belongs to the nerve endings of the party organization and comments reputation has a direct perception of the masses. Strengthen the party ahead of the \dal\hen the party members and cadres \does not have to be me\hardships, the last to\spirit to set the party's positive image among the people is important. Grass-roots party organizations \nse all people not happy not to see \s\honest faithful, diligent faith for the people. No need to avoid mentioning that, some members of our party can not stand the \y,\osion of temptation, thin, Xu Zhou, such abuse and corrupt bribery, malfeasance borers, and rats. Two, is to clean up, thin, Xu, Zhou's solution to restore the party's fresh and natural, solid and honest work style. Cleansing \sirable and behaviour, \d and cold, push\ss-roots party organizations \hen the sense of ordinary party members, participating in consciousness, unity consciousness. For reasons known, members of grass-roots party branches less mobile, less resources, and the construction of party organizations have some lag. Two studies, is to focus on the grass-roots party branches \nce the party members and cadres, \port.\Strong cleanup actions, style and rambling, presumptuous \s, pays special attention to party members and cadres \ng party of thought\oblem. \ding\d in the long-term development of our party's historical experience accumulated. Two is our party under the new historical conditions, strengthen the party's construction of a new \on movement.\-roots party organizations should always catch the hard work, results-oriented. Two educational outcomes are long-term oriented and become an important impetus for the work. \d have three kinds of consciousness %udy and education, basic learning lies in the doing. Only the Constitution address the series of party rules, and do solid work, be qualified party members had a solid ideological basis. Only the \ng\y, to form a \earn-do-do\e, and ultimately achieve the fundamental objective of education. This requires that the Organization
【答】C．
解：由图象可得：a?0，b?0，c?0，∴ab?0，ac?0，bc?0. 抛物线与x轴有两个交点，∴b2?4ac?0.当x=1时，y?0，即a?b?c?0. 当x=?1时，y?0，即a?b?c?0.从图象可得，抛物线对称轴在直线x=1的左边，即?个.
5. 如图，Rt△OAB的顶点O与坐标原点重合，∠AOB=90°，AO=2BO，当A点在反比例函数y? （x>0）的图象上移动时，B点坐标满足的函数解析式为【 】
learning education, need three kinds of consciousness: one is to establish an integrated awareness. \ning\car isTwo-wheel, bird wings, need to go hand in hand, one end can be neglected. Communist theoretician and man. Only by closely combining theory and practice together in order to truly realize their value. \arning\on, the Foundation is not strong, shaking; \net thousands of accounts. \s, going to \so that the \ng\ck to standard, so that the majority of party members \ng theory of nutrients, in the \ce party's purposes. Second, to establish a sense of depth. \ning\organic unity of the whole. \ning education, we need to explore integrating \ning\\nce\d the \ng\ple room instruction, \o a monotone for doing. Should exploration \n\ce of carrier, makes general grass-roots members can in \n\s \s sense, in \n\l makes party of theory brain into heart, put for people service concept outside of Yu shaped. Third, to adhere to long-term the awareness. Style construction on the road forever, \o catch the long-term. \nd education, by no means, assault-style wind-sport, but the recurrent education within the party. In recent years, the party's mass line education practice and \hree\cial education in grass-roots borne rich fruits, vast numbers of party members and cadres withstood the baptism of the spirit. \onger hold long-term, to establish and perfect the effective mechanism of the education, focusing on the creation of long-term education, strive to make the vast number of party members to maintain their vanguard Color, maintain the party's advanced nature and purity. Awareness-raising, antennas and atmosphere a discussion on how leading cadres of party members \n full swing up and down the country, party cadres as a \barometer and impetus. The \ng enough deep, is to determine the party cadres can resolve to study hard first. In the \he process, some cadres of himself, standing long, high awareness, that Constitution Party rules is simple, its not worth bothering some party cadres think speak series has nothing to do with the grass-roots work, water business learning series of speeches seen as window dressing. These \sual, and decadent\ning lacks motivation, a serious impediment to \once said, only a basic element of human thought patterns change dramatically, human destiny can make great improvement. The same, only party members andb?1，∴2a?b?0.因此7个代数式中，其值为正的式子的个数为42a1x