If an official of the government environmental protection department is to speak at this private environmental protection seminar, he must be a member of a private environmental protection organization. However, the meeting stipulates that as a member of a private environmental protection organization, it is not allowed to be both a government environmental protection official and Speak at this civil environmental seminar. If the above determination is true, Which of the following ____ items are also true. ['Among the speakers at this seminar, there are no government environmental protection officials.', 'Only members of civil environmental organizations can speak at this seminar.', "No one except the government's environmental protection officials spoke at this seminar.", 'Among the speakers at this seminar, there are no members of civil environmental groups.']