def get_hyphen_exp_wiki(sentences: list):
    """
    Gets all hyphen expressions contained in the sentences
    :param sentences: list containing strings
    :return: list containing hyphen expressions as string
    """
    hyphen_expressions = []
    for sent in sentences:
        tokens = sent.split()
        for i in range(len(tokens)):
            if tokens[i] == '@-@':
                hyphen_expressions.append(tokens[i - 1] + '-' + tokens[i + 1])
    return hyphen_expressions