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评分标准模式

General Mark Scheme Structure​

分值含义条件
M1, M2...Mark — 方法 / 结构分需要正确使用特定方法
A1, A2...Application — 应用分在 M mark 基础上正确实现
B1, B2...Bonus — 额外分独立于流程的正确做法

各题型 MS 模式对照​

Q1: Class + Constructor (4-5 marks)​

Typical MS Breakdown
  • M1: class keyword followed by class name and colon
  • A1: __init__ method defined with self as first parameter
  • A1: self.__attr = param for each private attribute (x3)
  • B1: Default attributes correctly initialised (if required)

Total: M1 + 3 x A1 = 4 marks

Q2: Getter Methods (3 marks)​

Typical MS Breakdown
  • M1: def GetX(self): correct signature
  • A1: return statement
  • A1: references self.__x

Total: M1 + A1 + A1 = 3 marks

Q3: Setter Methods (3 marks)​

Typical MS Breakdown
  • M1: def SetX(self, val): correct signature
  • A1: self.__x = val assignment
  • B1: Validation / range check (e.g. if val >= 0)

Total: M1 + A1 + B1 = 3 marks

Q4: Object + Method Call (2-4 marks)​

Typical MS Breakdown
  • M1: obj = ClassName(args) instantiation
  • A1: obj.Method() dot notation call
  • A1: Correct number and order of arguments passed

Total: M1 + A1 + A1 = 3 marks

Q5: Array of Objects + File (7 marks)​

Typical MS Breakdown
  • M1: Open file open("file.txt", "r")
  • M1: Loop through file for line in file:
  • M1: Parse line split(",") or strip()
  • A1: Create new object from parsed data
  • A1: Append to list arr.append(obj)
  • A1: Return list or process further
  • B1: file.close()

Total: 3 x M1 + 3 x A1 + B1 = 7 marks

Q6: Business Logic (6 marks)​

Typical MS Breakdown
  • M1: Loop through all objects in array
  • A1: Use getter methods to access data
  • A1: Correct logic (accumulation / comparison / condition)
  • M1: Correct output format (e.g. print with formatting)
  • A1: Handle edge cases (empty list, boundary values)
  • B1: Return value where appropriate

Total: 2 x M1 + 3 x A1 + B1 = 6 marks

Common MS Keywords​

MS Keyword含义例子
"Correct use of self"self 作为第一个参数且在 body 中使用self.__x
"Correct dot notation"对象名 + . + 方法名emp.GetName()
"Correct parameter passing"参数数量 + 类型匹配Employee("E01", "Ali")
"File handling"打开、读取、关闭open, readlines, close
"String manipulation"strip(), split(), castingint(parts[0])

扣分常见原因​

错误扣分影响
缺少 self 参数M mark 丢失
缺少 returnA mark 丢失
private 没加 __扣 1 mark per attribute
没有 file.close()扣 B1 mark
没用 getter/setter（直接用 obj.__attr）通常不扣分但推荐用 getter
循环逻辑错误（off-by-one）扣 A1 mark