Why does the data communication industry use the layered OSI reference model (Choose two.)（）。

A . To earn money for sch001． B . To keep his yard nice． C . To be able to work outdoors． D . To get exercise while working．

A .  They are both regions of lowest loss. B .  They are both regions of low reflections. C .  They are both regions of low index of refraction. D .  They are both regions of low chromatic dispersion. E .  They are both regions of low Polarization Mode Dispersion （PMD）.

A．The professor think it is potential to make things which we love tree treasure if days gone. B．The professor think we can make things true treasure if days gone. C．The professor think we should buy expensive things. D．The professor like to buy antique.

A．To discuss her grade in her last class. B．To inquire about auditing a class next term. C．To thank her professor for a good class. D．To ask questions about her thesis.

A．To demonstrate how the westward expansion of the United States came about. B．To illustrate Washington's contribution to the evolution of the United States. C．To explain why Jefferson was chosen to be one of the presidents on Mount Rushmore. D．To show why Jefferson's inclusion on Mount Rushmore was a contentious issu

A．To give an example of the instructional role of guilds. B．To correct a common misconception about guilds. C．To explain that guilds still exist in the modern world. D．To acknowledge that they share limited similarities with guilds.

A．They have their advanced language in form. of sound. B．They can express simple feelings such as hunger and pain. C．Some of them can communicate with people very well. D．All of them can use sound to express themselves.

A．To warn about possible risks involved in phytoremediation B．To help illustrate the potential of phytoremediation C．To show that hyperaccumulating plants grow in many regions of the world D．To explain how zinc contamination can be reduced

A.Herealizesthereisagreatdividebetweenhislifeandthatofblue-collarworkers. B.Helooksdownuponthemechanicalworkattheassemblyline. C.Hehasnotdonemuchtohelphisco-workersatthefactory. D.Hehasstayedatschooljustforthepurposeofescapingfromtherealworld.

A．E-mail B．Telephones C．Memorandums D．Instant messaging

A.Because it"s convenient． B.Because the man doesn"t need to spend money on furniture． C.Because the company can save money in the long run． D.Because the company doesn"t have to buy furniture for the man．

A．To describe how the differences between Pleistocene and Cambrian quartz reveal information about dating rocks B．To point out that the chemical composition of quartz makes it more difficult to date than other rocks C．To provide an example of how regional differences in rock sequences can make a particular rock difficult to date D．To explain that rocks are difficult to use for dating because their chemical compositions always remain the same over time

A．To ask for advice B．To ask questions C．To make up for lessons D．To get his signature 此题为多项选择题。

A．It is an example of a work copied in another medium. B．Drawing was typical of the way that artists were educated. C．The sketch was a historical account of an important event. D．The size of the drawing made it an exceptional work of art.

A.To help his students learn English． B.To make his students work harder． C.To give his students some advice．

A．to ask the professor about an article she wrote B．to ask the professor’s opinion about an art exhibition C．to ask the professor to approve a topic of a paper． D．to ask the professor to write to her colleague on the student’s behalf

A．To indicate to the professor that she is familiar with the drip technique B．To find out if she can see an original painting by Jackson Pollock in the university gallery． C．To make a comparison between her paintings and those of Jackson Pollock． D．To express interest in taking the professor’s class．