使用字符开始和结束位置的多个唯一字符串替换

def replace_unique_strings(text, replacements):
    """
    Replace multiple unique strings in text based on start and end positions.
    
    :param text: The original text.
    :param replacements: A list of tuples (start_pos, end_pos, new_string).
    :return: The modified text.
    """
    for start_pos, end_pos, new_string in sorted(replacements, reverse=True):
        text = text[:start_pos] + new_string + text[end_pos:]
    return text

# Example usage
original_text = "Hello, world! This is a test. Goodbye, world!"
replacements = [(7, 12, "universe"), (27, 32, "example")]

modified_text = replace_unique_strings(original_text, replacements)
print(modified_text)  # Output: "Hello, universe! This is a test. Goodbye, example!"