[{"id":2768,"subject":"历史","grade":"七年级","stage":"初中","type":"选择题","content":"考古学家在某遗址中发现了大量炭化稻谷、干栏式建筑遗迹和刻画符号的陶器，这些发现最有可能属于哪个新石器时代文化？","answer":"A","explanation":"题干中提到的‘炭化稻谷’表明该地区以水稻种植为主，而水稻主要种植于长江流域；‘干栏式建筑’是适应潮湿环境的典型建筑形式，常见于南方地区；刻画符号的陶器也见于河姆渡遗址。河姆渡文化位于浙江余姚，属于长江流域的新石器时代文化，距今约7000年，符合上述特征。半坡文化位于黄河流域，以粟作农业和半地穴式房屋为特点；大汶口文化和红山文化也主要分布在北方，且不以水稻为主要作物。因此，正确答案为A。","solution_steps":"","common_mistakes":"","learning_suggestions":"","difficulty":"简单","points":1,"is_active":1,"created_at":"2026-01-12 10:40:42","updated_at":"2026-01-12 10:40:42","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":"河姆渡文化","is_correct":1},{"id":"B","content":"半坡文化","is_correct":0},{"id":"C","content":"大汶口文化","is_correct":0},{"id":"D","content":"红山文化","is_correct":0}]},{"id":2412,"subject":"数学","grade":"八年级","stage":"初中","type":"选择题","content":"某学生在研究两个三角形时发现，△ABC 和 △DEF 中，∠A = ∠D，AB = DE，且 ∠B = ∠E。若他想证明这两个三角形全等，应使用以下哪个判定定理？此外，若 AC = 5 cm，BC = 7 cm，∠C = 60°，则根据全等性质，DF 的长度应为多少？","answer":"A","explanation":"题目中给出 ∠A = ∠D，AB = DE，∠B = ∠E，即两个角和它们的夹边分别相等，符合 ASA（角-边-角）全等判定定理。由于 AB 是 ∠A 与 ∠B 的夹边，对应边 DE 是 ∠D 与 ∠E 的夹边，因此 △ABC ≌ △DEF（ASA）。根据全等三角形的性质，对应边相等，AC 对应 DF，已知 AC = 5 cm，故 DF = 5 cm。因此正确答案为 A。","solution_steps":"","common_mistakes":"","learning_suggestions":"","difficulty":"中等","points":1,"is_active":1,"created_at":"2026-01-10 12:23:21","updated_at":"2026-01-10 12:23:21","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":"ASA，DF = 5 cm","is_correct":1},{"id":"B","content":"AAS，DF = 7 cm","is_correct":0},{"id":"C","content":"SAS，DF = 5 cm","is_correct":0},{"id":"D","content":"ASA，DF = 7 cm","is_correct":0}]},{"id":1796,"subject":"数学","grade":"七年级","stage":"初中","type":"选择题","content":"某校七年级组织学生参加数学兴趣小组活动，报名参加A、B两个小组的人数共45人。已知参加A组的人数比B组人数的2倍少3人。设参加B组的人数为x，则下列方程正确的是：","answer":"A","explanation":"根据题意，设参加B组的人数为x，则参加A组的人数比B组的2倍少3人，即A组人数为2x - 3。两组总人数为45人，因此可列出方程：x + (2x - 3) = 45。选项A正确。选项B错误，因为A组是比2倍少3，不是多3；选项C只考虑了A组人数等于45，忽略了总人数包含两组；选项D虽然变形后等价，但表达方式不规范，未明确体现A组人数的代数式，不符合设未知数列方程的标准形式。因此，最准确且符合题意的方程是A。","solution_steps":null,"common_mistakes":null,"learning_suggestions":null,"difficulty":"中等","points":1,"is_active":1,"created_at":"2026-01-06 16:12:21","updated_at":"2026-01-06 16:12:21","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":"x + (2x - 3) = 45","is_correct":1},{"id":"B","content":"x + (2x + 3) = 45","is_correct":0},{"id":"C","content":"2x - 3 = 45","is_correct":0},{"id":"D","content":"x + 2x = 45 - 3","is_correct":0}]},{"id":1027,"subject":"数学","grade":"初一","stage":"初中","type":"填空题","content":"某班级组织了一次环保知识竞赛，共收集了50份有效问卷。统计结果显示，有32名学生表示经常进行垃圾分类，有25名学生表示每天步行或骑自行车上学。已知每位学生至少符合其中一项环保行为，那么同时做到垃圾分类和绿色出行的学生至少有___人。","answer":"7","explanation":"根据容斥原理，设同时做到两项的学生人数为x。总人数 = 垃圾分类人数 + 绿色出行人数 - 同时做到两项的人数。即：50 = 32 + 25 - x，解得x = 7。因此，同时做到两项的学生至少有7人。","solution_steps":null,"common_mistakes":null,"learning_suggestions":null,"difficulty":"简单","points":1,"is_active":1,"created_at":"2025-12-30 05:45:38","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":2150,"subject":"数学","grade":"七年级","stage":"初中","type":"选择题","content":"某学生在解方程时，将方程 2x + 5 = 13 的两边同时减去5，得到 2x = 8，然后再将两边同时除以2，得到 x = 4。这名学生使用的解题方法体现了等式的哪一条基本性质？","answer":"D","explanation":"该学生先对等式两边同时减去5，再同时除以2，整个过程体现了对等式两边进行相同运算时，等式依然成立这一基本性质。虽然选项B和C分别描述了其中一步所依据的性质，但整个解题过程综合体现了等式的基本性质：等式两边同时进行相同的运算（加、减、乘、除同一个数，除数不为零），等式仍然成立。因此，最全面且准确的答案是D。","solution_steps":"","common_mistakes":"","learning_suggestions":"","difficulty":"简单","points":1,"is_active":1,"created_at":"2026-01-09 13:00:46","updated_at":"2026-01-09 13:00:46","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":"A","content":"等式两边同时加上同一个数，等式仍然成立","is_correct":0},{"id":"B","content":"等式两边同时减去同一个数，等式仍然成立","is_correct":0},{"id":"C","content":"等式两边同时乘或除以同一个不为零的数，等式仍然成立","is_correct":0},{"id":"D","content":"等式两边同时进行相同的运算，等式仍然成立","is_correct":1}]},{"id":2183,"subject":"数学","grade":"七年级","stage":"初中","type":"选择题","content":"某学生在计算两个有理数的和时，误将其中一个加数的符号看错，导致结果比正确答案大了8。已知这两个有理数互为相反数，那么这两个数的绝对值是多少？","answer":"B","explanation":"设这两个互为相反数的有理数为 a 和 -a。正确的和应为 a + (-a) = 0。某学生看错其中一个加数的符号，假设将 -a 看成 a，则计算结果为 a + a = 2a。题目说错误结果比正确答案大8，即 2a - 0 = 8，解得 a = 4。因此这两个数的绝对值是 |a| = 4。","solution_steps":"","common_mistakes":"","learning_suggestions":"","difficulty":"中等","points":1,"is_active":1,"created_at":"2026-01-09 14:21:04","updated_at":"2026-01-09 14:21:04","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":"2","is_correct":0},{"id":"B","content":"4","is_correct":1},{"id":"C","content":"6","is_correct":0},{"id":"D","content":"8","is_correct":0}]},{"id":583,"subject":"数学","grade":"初一","stage":"小学","type":"选择题","content":"9","answer":"待完善","explanation":"解析待完善","solution_steps":null,"common_mistakes":null,"learning_suggestions":null,"difficulty":"简单","points":1,"is_active":1,"created_at":"2025-12-29 20:11:43","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":737,"subject":"数学","grade":"初一","stage":"小学","type":"填空题","content":"某学生调查了班级同学每天用于课外阅读的时间（单位：分钟），将数据整理后绘制成频数分布直方图。已知阅读时间在30～40分钟这一组的频数是8，频率是0.2，则该学生所在班级的总人数是____。","answer":"40","explanation":"根据频率的定义，频率 = 频数 ÷ 总人数。题目中给出频数为8，频率为0.2，因此总人数 = 频数 ÷ 频率 = 8 ÷ 0.2 = 40。该题考查数据的收集、整理与描述中的频率与频数关系，属于简单计算题。","solution_steps":null,"common_mistakes":null,"learning_suggestions":null,"difficulty":"简单","points":1,"is_active":1,"created_at":"2025-12-29 23:09:43","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":283,"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描出三个点 A(1, 2)、B(3, 2) 和 C(3, 5)，然后连接这三个点形成一个三角形。这个三角形最可能的形状是：","answer":"B","explanation":"首先，根据坐标描点：点 A(1, 2) 和点 B(3, 2) 的 y 坐标相同，说明 AB 是一条水平线段，长度为 |3 - 1| = 2。点 B(3, 2) 和点 C(3, 5) 的 x 坐标相同，说明 BC 是一条竖直线段，长度为 |5 - 2| = 3。因此，AB 与 BC 互相垂直，在点 B 处形成直角。根据定义，有一个角是直角的三角形是直角三角形。所以这个三角形最可能是直角三角形。","solution_steps":null,"common_mistakes":null,"learning_suggestions":null,"difficulty":"简单","points":1,"is_active":1,"created_at":"2025-12-29 15:31:27","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":"等边三角形","is_correct":0},{"id":"B","content":"直角三角形","is_correct":1},{"id":"C","content":"钝角三角形","is_correct":0},{"id":"D","content":"锐角三角形","is_correct":0}]},{"id":399,"subject":"数学","grade":"初一","stage":"小学","type":"选择题","content":"某学生在整理班级同学的课外阅读时间数据时，发现一周内每天阅读时间（单位：分钟）分别为：20、25、30、35、40、45、50。若该学生想用一个统计图来直观展示这些数据的变化趋势，以下哪种统计图最合适？","answer":"B","explanation":"题目中给出的数据是按时间顺序（一周内每天）记录的阅读时间，目的是展示‘变化趋势’。折线图能够清晰地反映数据随时间变化的趋势，因此最适合用于此类情境。扇形图主要用于表示各部分占整体的比例，不适合展示趋势；条形图适合比较不同类别的数据，但不如折线图直观体现变化；频数分布直方图用于展示数据分布情况，不强调时间顺序。因此，正确答案是B。","solution_steps":null,"common_mistakes":null,"learning_suggestions":null,"difficulty":"简单","points":1,"is_active":1,"created_at":"2025-12-29 17:16:10","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":"扇形图","is_correct":0},{"id":"B","content":"折线图","is_correct":1},{"id":"C","content":"条形图","is_correct":0},{"id":"D","content":"频数分布直方图","is_correct":0}]}]