30. What is the argument over Uber according to the passage?

　　A. Whether it guarantees customers' safety.

　　B. Whether it provides reliable services.

　　C. Whether it lowers customers' expenses.

　　D. Whether it can compete with standard taxis.

　　31. What will be talked about in the following paragraphs?

　　A. Existing regulations and laws.

　　B. Necessary improvements of current laws.

　　C. Further development of Airbnb and Uber.

　　D. More downsides of Airbnb and Uber.

　　D

　　The old shopkeeper led me through to the back of the shop. The room was filled with boxes and dusty photogr ..........