def build_query_string(query_words):
    """Builds an OR concatenated string for querying the Twitter Search API.
    Args:
        query_words (list): list of words to be concatenated.

    Returns:
        list: List of words concatenated with OR.
    """
    result = ''.join(
        [q + ' OR ' for q in query_words[0:(len(query_words) - 1)]])
    return result + str(query_words[len(query_words) - 1])