如何在python中实现数学测验的计时器？

import time
import random

def generate_question():
    """生成一个简单的数学问题"""
    num1 = random.randint(1, 10)
    num2 = random.randint(1, 10)
    operation = random.choice(['+', '-', '*', '/'])
    
    if operation == '+':
        answer = num1 + num2
    elif operation == '-':
        answer = num1 - num2
    elif operation == '*':
        answer = num1 * num2
    elif operation == '/':
        # 确保除法结果是整数
        num1 = num1 * num2
        answer = num1 / num2
    
    return f"{num1} {operation} {num2}", answer

def main():
    num_questions = 5
    correct_answers = 0
    total_time = 0

    for i in range(num_questions):
        question, correct_answer = generate_question()
        print(f"Question {i + 1}: {question}")

        start_time = time.time()
        user_answer = input("Your answer: ")
        end_time = time.time()

        try:
            user_answer = float(user_answer)
            if user_answer == correct_answer:
                print("Correct!")
                correct_answers += 1
            else:
                print(f"Wrong! The correct answer is {correct_answer}")
        except ValueError:
            print(f"Invalid input! The correct answer is {correct_answer}")

        question_time = end_time - start_time
        total_time += question_time
        print(f"Time taken: {question_time:.2f} seconds\n")

    print(f"You answered {correct_answers} out of {num_questions} questions correctly.")
    print(f"Total time taken: {total_time:.2f} seconds")
    print(f"Average time per question: {total_time / num_questions:.2f} seconds")

if __name__ == "__main__":
    main()

python math_quiz.py