Directions: In this part, there is a passage with ten blanks. For each blank there are four choices marked A, B, C, and D. Choose the best answer for each blank and mark your answer on the ANSWER SHEET.
　　Cloud computing(云计算) means storing and accessing data and programs over the Internet instead of your computer’s hard drive. It (46) _____ computing over a network, where a program or application may run on many connected computers at the same time.
　　For some, cloud computing is a metaphor(隐喻) for the Internet. It (47) _____ uses connected hardware machines called servers. Individual users can use the server’s processing power to run an application, store data, or (48) _____ any other computing task.
　　For businesses, cloud computing is an ideal way to reduce (49) _____. For example, companies may buy services in the cloud. That is to say, instead of (50) _____ applications on every single computer in the company, cloud computing would allow workers to log into a Web-based service (a cloud) which hosts all the (51) _____ individual users would need for their job.
　　While cloud computing could change the entire computer industry, there are still some (52) _____ about the security of the data stored on the remote machines. It is true that it promises to save a lot of work. However, this technology (53) _____ a fundamental question. Is it safe to store one’s data on someone else’s computer? The cloud service provider needs to establish relevant policies that describe (54) _____ the data of each cloud user will be accessed and used. Cloud service users should also be able to encrypt(加密) (55) _____ that is processed or stored within the cloud to prevent unauthorized access._____