检查字符串中是否存在两个子字符串之一

def check_substrings(main_string, substrings):
    for substring in substrings:
        if substring in main_string:
            return True
    return False

# 示例使用
main_string = "Hello, world!"
substrings_to_check = ["world", "planet"]

result = check_substrings(main_string, substrings_to_check)
print(result)  # 输出: True，因为"world"是main_string的子字符串

def check_substrings_case_insensitive(main_string, substrings):
    main_string_lower = main_string.lower()
    for substring in substrings:
        if substring.lower() in main_string_lower:
            return True
    return False