题目内容：

Researchers at the University of Chicago have trained an artificial intelligence( 人工智能) system, to write fake( 伪 造 的 ) reviews( 评 论 ) on Yelp, a website showing customers reviews on shopping or something else, and it's pretty hard to tell them apart from a human review.

Their study, which will be presented at the ACM Conference on Computer and Communications Security in October, aimed to throw attention onto how easily these systems can write reviews like humans and how damaging they can become if they’re not monitored properly.

Since many small businesses depend on online reviews to help grow and keep their reputation, a future where someone—like a rival or angry customer—could crazily fill their page with negative reviews written by a machine is pretty worrying.

And, according to the research team, the threat goes far beyond fake reviews on Yelp. “In general the threat is bigger,” Ben Y. Zhao, one of the authors of the study, said. “I think the threat towards society is large and it really misleads users and shakes our belief in what is real and what is not. I think that' s going to be even unimaginable.”

To test how believable these reviews are, the researchers invited 40 volunteers and had AI make five fake reviews for 40 actual restaurants. The volunteers were asked how useful they thought the review was and whether or not they thought it was fake. The AI reviews was regarded as  “effectively unrecognizable ” from real reviews，according to the study. Further, the fake reviews were given a 3.15 "usefulness" rating, compared to a 3.28 rating for human reviews.

1.What can the new artificial intelligence system do according to the passage？

A. It can help train new reviewers.

B. It can tell the real reviews from the fake ones.

C. It can write human-like reviews.

D. It can easily damage the businesses.

2.What does the underlined word "rival'' mean in the passage?

A. A person who respects you deeply.

B. A person who is against you.

C. A person who loves to give fake reviews.

D. A person who can control you from distance.

3.What can we infer from Ben Y. Zhao's remarks?

A. Artificial intelligence can put the society in danger.

B. The artificial intelligence is only used by the researchers

C. Ben Y. Zhao is optimistic about the further development of artificial intelligence.

D. The artificial intelligence will help people shake.

4.What is the best title for the passage?

A. Tips on Giving Reviews.    B. How to Tell the Fake Reviews.

C. Development of AI in Review on Yelp.    D. AI is coming to Steal Your Reviews.