def build_available_time_string(availabilities):
    """
    Build a string eliciting for a possible time slot among at least two availabilities.
    """
    prefix = 'We have availabilities at '
    if len(availabilities) > 3:
        prefix = 'We have plenty of availability, including '

    prefix += build_time_output_string(availabilities[0])
    if len(availabilities) == 2:
        return '{} and {}'.format(prefix, build_time_output_string(availabilities[1]))

    return '{}, {} and {}'.format(prefix, build_time_output_string(availabilities[1]), build_time_output_string(availabilities[2]))