a guest speaker的用法和样例：
- Sir David Bellamy was a guest speaker at the conference.
- "A guest speaker was invited to give a talk to patients in a madhouse.He began his talk by asking a question: “Why are we all here?
- To give you an example of selective listening, let me share with you a story I heard about a medical doctor who was invited as a guest speaker to address a group of alcoholics.
- The guest speaker will be our old friend John Lewis.
- She made a guest appearance on his TV show.