根据短文理解, 从A、B、C、D四个选项中选择最佳答案填空。

    An old friend from the US whom I was looking forward to staying with telephoned from the airport to tell me that he had arrived. I was still at the 1  at that time, but I had got everything ready for his arrival. After letting him know where my house was, I told him that I had left the  2under the doormat(门垫),  3  I was likely to be home rather late. I told him to go into the 4 and help himself to food and drink. Two hours later my friend 5 me from the house. At the moment, he said, he was listening to some of my records after having just had a truly wonderful 6 . He had found a cooker and  7  two eggs and he helped himself to some cold chicken from the ice box. He said he was drinking a glass of orange juice and he hoped I would 8him. When I asked him if he had reached the house without difficulty, he answered, "I was not able to find the key,  9 luckily, the living-room windows Just by the apple tree were left open and you know what I could do." I listened to all this in 10 . In front of my living-room there was no apple tree at all.

    Students taking Georgia Tech's online Knowledge-Based Artificial Intelligence course received some surprising news. Jill Watson one of the nine teaching assistants(TAs) that had helped them finish the challenging course for the past five months was not a ‘‘she'' but an “it”—an intelligent robot!

    Watson is the brainchild of Ashok Goel, who teaches the popular online course. The Professor-of Computer and Cognitive Science in the School of Interactive Computing came up with the idea as a way to deal with a number of questions posed by students in the online forums(论坛). According to Goel, every time the course is offered, the 300 or so students that enroll post over 10,000 questions which are often repetitive. This led Goel to wonder if a smart robot would handle the questions which require standard responses.

    Having worked' with IBM's Watson technology platform in the, the professor knew it would be ideal for his artificial TA: Jill Watson. The artificial intelligence system that uses natural language processing and machine learning to analyze large amounts of data has even been cleverer than human competitors on the television show. It would therefore easily be able to handle routine questions that required little “thinking”.

    The professor and his team of graduate students began by populating Jill's memory with 40,000 questions and answers from past terms. Then came the testing stage. At first, Jill was not very good and often gave strange answers. It often got stuck on certain keywords. By the end of the semester, Jill had attained enough knowledge and skills to participate in forums without any management from Goel, or the other assistants.

①网络成为了社会生产的新工具、经济贸易的新途径

②网络推动了社会进步，提升了经济发展水平

③基于互联网的大数据正在改变我们的生活和理解世界的方式，成为众多新发明和新服务的源泉

④互联网为文化传播和科技创新搭建新平台