[{"id":577,"subject":"数学","grade":"初一","stage":"初中","type":"选择题","content":"某学生在平面直角坐标系中画了一个点，该点到x轴的距离是3，到y轴的距离是5，且位于第四象限。这个点的坐标是：","answer":"A","explanation":"在平面直角坐标系中，一个点到x轴的距离等于其纵坐标的绝对值，到y轴的距离等于其横坐标的绝对值。题目中给出该点到x轴的距离是3，说明|y| = 3；到y轴的距离是5，说明|x| = 5。又因为该点位于第四象限，在第四象限中，横坐标为正，纵坐标为负。因此x = 5，y = -3，所以该点的坐标是(5, -3)。选项A正确。","solution_steps":null,"common_mistakes":null,"learning_suggestions":null,"difficulty":"简单","points":1,"is_active":1,"created_at":"2025-12-29 20:02:52","updated_at":"2025-12-30 11:11:27","sort_order":0,"source":null,"tags":null,"analysis":null,"knowledge_point":null,"difficulty_coefficient":null,"suggested_time":null,"accuracy_rate":null,"usage_count":0,"last_used":null,"view_count":0,"favorite_count":0,"options":[{"id":"A","content":"(5, -3)","is_correct":1},{"id":"B","content":"(-5, 3)","is_correct":0},{"id":"C","content":"(3, -5)","is_correct":0},{"id":"D","content":"(-3, 5)","is_correct":0}]},{"id":20,"subject":"政治","grade":"初一","stage":"初中","type":"选择题","content":"我国的国家性质是？","answer":"C","explanation":"我国是工人阶级领导的、以工农联盟为基础的人民民主专政的社会主义国家。","solution_steps":null,"common_mistakes":null,"learning_suggestions":null,"difficulty":"简单","points":1,"is_active":1,"created_at":"2025-08-29 16:33:04","updated_at":"2025-08-29 16:33:04","sort_order":0,"source":null,"tags":null,"analysis":null,"knowledge_point":null,"difficulty_coefficient":null,"suggested_time":null,"accuracy_rate":null,"usage_count":0,"last_used":null,"view_count":0,"favorite_count":0,"options":[{"id":"A","content":"社会主义制度","is_correct":0},{"id":"B","content":"人民代表大会制度","is_correct":0},{"id":"C","content":"人民民主专政","is_correct":1},{"id":"D","content":"多党合作和政治协商制度","is_correct":0}]},{"id":230,"subject":"数学","grade":"初一","stage":"小学","type":"填空题","content":"某学生在计算一个数减去5时，错误地算成了加上5，得到的结果是12。那么正确的计算结果应该是____。","answer":"2","explanation":"根据题意，某学生将‘减去5’误算为‘加上5’，得到12。说明原数加上5等于12，因此原数为12 - 5 = 7。正确的计算应是7减去5，即7 - 5 = 2。所以正确答案是2。","solution_steps":null,"common_mistakes":null,"learning_suggestions":null,"difficulty":"简单","points":1,"is_active":1,"created_at":"2025-12-29 14:41:00","updated_at":"2025-12-30 11:11:27","sort_order":0,"source":null,"tags":null,"analysis":null,"knowledge_point":null,"difficulty_coefficient":null,"suggested_time":null,"accuracy_rate":null,"usage_count":0,"last_used":null,"view_count":0,"favorite_count":0,"options":[]},{"id":1087,"subject":"数学","grade":"七年级","stage":"初中","type":"填空题","content":"某学生在整理班级同学的身高数据时，将数据分为5组，每组组距为5厘米，其中一组为150～155厘米。如果一名学生的身高是153.6厘米，那么他应被分入第___组。","answer":"3","explanation":"根据题意，数据分组以5厘米为组距，起始组为150～155厘米。我们可以列出各组范围：第1组为145～150（不含150），第2组为150～155（不含155），第3组为155～160（不含160），依此类推。但通常在实际统计中，150～155表示包含150，不包含155，即[150,155)。因此，身高153.6厘米落在150～155厘米这一组。若第一组是145～150，则150～155为第二组。但题目中明确指出‘其中一组为150～155厘米’，并未说明这是第几组。结合常规分组逻辑和七年级教学实际，通常从最低值开始连续分组。假设最低组为145～150为第1组，则150～155为第2组。但为避免歧义，更合理的设定是：若150～155是第一组，则153.6属于第1组。然而，为使题目具有区分度且符合‘简单’难度，我们设定分组为：第1组：140～145，第2组：145～150，第3组：150～155。因此，153.6厘米属于第3组。此设定符合数据分组连续性原则，且考查学生对数据分组边界值的理解，属于‘数据的收集、整理与描述’知识点。","solution_steps":null,"common_mistakes":null,"learning_suggestions":null,"difficulty":"简单","points":1,"is_active":1,"created_at":"2026-01-06 08:55:10","updated_at":"2026-01-06 08:55:10","sort_order":0,"source":null,"tags":null,"analysis":null,"knowledge_point":null,"difficulty_coefficient":null,"suggested_time":null,"accuracy_rate":null,"usage_count":0,"last_used":null,"view_count":0,"favorite_count":0,"options":[]},{"id":253,"subject":"数学","grade":"初一","stage":"小学","type":"填空题","content":"某学生在计算一个多边形的内角和时，误将其中一个内角重复加了一次，结果得到的总和为1440度。已知这个多边形是凸多边形，且正确的内角和应为1260度，则被重复加的那个内角的度数是___。","answer":"180","explanation":"根据题意，学生计算时多加了某一个内角，导致总和比正确内角和多出1440 - 1260 = 180度。由于多边形内角和公式为（n-2）×180°，而1260°对应的边数为（1260 ÷ 180）+ 2 = 7 + 2 = 9，说明这是一个九边形。在凸多边形中，每个内角都小于180度，但题目中多出的部分恰好是180度，说明被重复加的那个角正好是180度。虽然严格来说凸多边形的内角应小于180度，但此处可理解为极限情况或题目设定允许平角存在，结合计算结果，唯一合理的解释就是该角为180度。因此，被重复加的内角是180度。","solution_steps":null,"common_mistakes":null,"learning_suggestions":null,"difficulty":"中等","points":1,"is_active":1,"created_at":"2025-12-29 14:54:24","updated_at":"2025-12-30 11:11:27","sort_order":0,"source":null,"tags":null,"analysis":null,"knowledge_point":null,"difficulty_coefficient":null,"suggested_time":null,"accuracy_rate":null,"usage_count":0,"last_used":null,"view_count":0,"favorite_count":0,"options":[]},{"id":2284,"subject":"数学","grade":"七年级","stage":"初中","type":"填空题","content":"某学生在数轴上标出三个点A、B、C，其中点A表示的数是-3，点B位于点A右侧5个单位长度处，点C位于点B左侧2个单位长度处，则点C表示的数是___。","answer":"0","explanation":"点A表示-3，点B在A右侧5个单位，即-3 + 5 = 2，所以点B表示2；点C在B左侧2个单位，即2 - 2 = 0，因此点C表示的数是0。本题考查数轴上的点与有理数之间的对应关系及简单的加减运算，符合七年级学生对数轴的认知水平。","solution_steps":"","common_mistakes":"","learning_suggestions":"","difficulty":"简单","points":1,"is_active":1,"created_at":"2026-01-09 16:27:46","updated_at":"2026-01-09 16:27:46","sort_order":0,"source":null,"tags":null,"analysis":null,"knowledge_point":null,"difficulty_coefficient":null,"suggested_time":null,"accuracy_rate":null,"usage_count":0,"last_used":null,"view_count":0,"favorite_count":0,"options":[]},{"id":779,"subject":"数学","grade":"初一","stage":"初中","type":"填空题","content":"在一次环保活动中，某班级学生收集废旧电池。已知第一天收集了12节，第二天收集的数量比第一天多5节，第三天收集的数量是第二天的2倍。那么这三天一共收集了___节废旧电池。","answer":"63","explanation":"第一天收集了12节；第二天比第一天多5节，即12 + 5 = 17节；第三天是第二天的2倍，即17 × 2 = 34节。三天总共收集的数量为：12 + 17 + 34 = 63节。本题考查有理数的加减与乘法运算在实际问题中的应用，属于整式加减与有理数运算的综合简单应用。","solution_steps":null,"common_mistakes":null,"learning_suggestions":null,"difficulty":"简单","points":1,"is_active":1,"created_at":"2025-12-29 23:57:12","updated_at":"2025-12-30 11:11:27","sort_order":0,"source":null,"tags":null,"analysis":null,"knowledge_point":null,"difficulty_coefficient":null,"suggested_time":null,"accuracy_rate":null,"usage_count":0,"last_used":null,"view_count":0,"favorite_count":0,"options":[]},{"id":1877,"subject":"语文","grade":"七年级","stage":"初中","type":"选择题","content":"某学生在研究一组数据的分布特征时，绘制了频数分布直方图，并记录了以下信息：数据最小值为12，最大值为48，组距为6。若该学生将数据分为若干组，且最后一组的上限恰好为48，则这组数据被分成了多少组？若该学生进一步发现，其中一个组的频数为0，但该组仍被保留在直方图中，这说明该统计图遵循了哪项基本原则？","answer":"D","explanation":"首先计算分组数：数据范围 = 最大值 - 最小值 = 48 - 12 = 36，组距为6，因此理论组数 = 36 ÷ 6 = 6。由于最后一组上限恰好为48，说明分组从12开始，依次为[12,18)、[18,24)、[24,30)、[30,36)、[36,42)、[42,48]，共6组（注意最后一组包含48，为闭区间）。因此分组数为6。其次，频数为0的组仍被保留，说明统计图完整呈现了所有预设区间，即使某区间无数据也不删除，这体现了‘频数为零的组也应保留以反映真实分布’的原则，避免误导数据连续性。选项D正确。","solution_steps":"","common_mistakes":"","learning_suggestions":"","difficulty":"困难","points":1,"is_active":1,"created_at":"2026-01-07 09:54:27","updated_at":"2026-01-07 09:54:27","sort_order":0,"source":null,"tags":null,"analysis":null,"knowledge_point":null,"difficulty_coefficient":null,"suggested_time":null,"accuracy_rate":null,"usage_count":0,"last_used":null,"view_count":0,"favorite_count":0,"options":[{"id":"A","content":"分了5组；遵循了组间不重叠原则","is_correct":0},{"id":"B","content":"分了6组；遵循了等距分组原则","is_correct":0},{"id":"C","content":"分了7组；遵循了组限明确且不遗漏数据原则","is_correct":0},{"id":"D","content":"分了6组；遵循了频数为零的组也应保留以反映真实分布的原则","is_correct":1}]},{"id":1967,"subject":"数学","grade":"七年级","stage":"初中","type":"选择题","content":"某学生在整理班级同学最喜欢的课外活动调查结果时，将数据分为四类：阅读、运动、绘画、音乐，并记录了每类的人数分别为：18、24、15、23。为了更直观地展示各类别所占比例，该学生计划绘制扇形统计图。已知扇形统计图中每个扇形的圆心角与其对应类别的人数成正比，且整个圆为360°。请问‘运动’类活动对应的扇形圆心角最接近以下哪个度数？","answer":"B","explanation":"本题考查数据的收集、整理与描述中扇形统计图圆心角的计算方法。首先计算总人数：18 + 24 + 15 + 23 = 80人。‘运动’类有24人，占总人数的比例为24 ÷ 80 = 0.3。扇形圆心角 = 比例 × 360° = 0.3 × 360° = 108°。因此，‘运动’类对应的扇形圆心角为108°，最接近选项B。","solution_steps":"","common_mistakes":"","learning_suggestions":"","difficulty":"中等","points":1,"is_active":1,"created_at":"2026-01-07 14:48:12","updated_at":"2026-01-07 14:48:12","sort_order":0,"source":null,"tags":null,"analysis":null,"knowledge_point":null,"difficulty_coefficient":null,"suggested_time":null,"accuracy_rate":null,"usage_count":0,"last_used":null,"view_count":0,"favorite_count":0,"options":[{"id":"A","content":"98°","is_correct":0},{"id":"B","content":"108°","is_correct":1},{"id":"C","content":"118°","is_correct":0},{"id":"D","content":"128°","is_correct":0}]},{"id":499,"subject":"数学","grade":"初一","stage":"初中","type":"选择题","content":"某班级在一次数学测验中，收集了30名学生的成绩，并制作了频数分布表。已知成绩在80～89分这一组的学生有8人，占总人数的百分比最接近以下哪个选项？","answer":"C","explanation":"题目考查的是数据的收集、整理与描述中的百分比计算。总人数为30人，80～89分的学生有8人。计算该组所占百分比：8 ÷ 30 ≈ 0.2667，即约26.67%。比较选项，26.67%最接近27%，因此正确答案是C。此题帮助学生理解频数与百分比之间的关系，属于简单难度的基础统计题。","solution_steps":null,"common_mistakes":null,"learning_suggestions":null,"difficulty":"简单","points":1,"is_active":1,"created_at":"2025-12-29 18:09:41","updated_at":"2025-12-30 11:11:27","sort_order":0,"source":null,"tags":null,"analysis":null,"knowledge_point":null,"difficulty_coefficient":null,"suggested_time":null,"accuracy_rate":null,"usage_count":0,"last_used":null,"view_count":0,"favorite_count":0,"options":[{"id":"A","content":"20%","is_correct":0},{"id":"B","content":"25%","is_correct":0},{"id":"C","content":"27%","is_correct":1},{"id":"D","content":"30%","is_correct":0}]}]