颈椎病发病与哪一项不相关（） A.先天性遗传 B.自身免疫 C.慢性创伤 D.慢性劳

根据首字母填空。

     We are all busy talking about and using the Internet (互联网), but how many of us know the h__1__

of the Internet?

     Many people are surprised when they find that the I__2__ was set up in the 1960s. At that time,

computers were large and e__3__ . Computer networks (网络) didn't work well. If one computer in

the network broke down, then the whole network stopped. So a new network system had to be set up.

It should be good e__4__ to be used by many different computers. If part of the network was not

working, information could be sent through a__5__ part. In this way computer network system would

keep on w__6__ all the time.

     At f__7__ the Internet was only used by the government, but, in the early 1970s, universities, hospitals and banks were allowed to use it too. H__8__, computers were still very expensive and the Internet

was d__9__ to use. By the start of the 1990s, c__10__ became cheaper and easier to use. Scientists

had also developed software that made 'surfing' (浏览) the Internet more convenient.

     Today it is easy to get on-line (上网) and it is said that m__11__ of people use the Internet everyday. Sending e-mail is more and more p__12__ among students.

The Internet has now become one of the most important parts of people's life.

I say goodbye to             friend.[ ]

A. my    

B. me    

C. I

入射光线与平面镜的夹角为40°，则反射角为______°；若入射光线垂直射向平面镜，此时的入射角是______°．

在Visual FoxPro中调用表单文件mf1的正确命令是【 】。

A．DO mf1

B．DO FROM mf1

C．DO FORM mf1

D．RUN mf1

小明是一所大学的学生21岁。某日他到某家录像厅看录像，发现这里竟然组织播放内容极其下流的淫秽录像，于是小明将此事告诉了他的老师夏某。夏某就向公安机关报告了此事。公安机关经过审查后决定立案侦查此案。此后，小明又匿名向公安机关寄去了书面证明材料，陈述了自己的所见所闻。夏某也向公安机关写了一份书面材料，将小明告诉给自己的情况提供给了公安局。公安局将录像厅的老板传唤至公安机关讯问。该老板许某承认了自己以营利为目的而播放淫秽录像的事实。公安机关也从许某的录像厅里搜出多盘淫秽录像带。公安机关将许某的录像设备及录像带全部拍成照片以便移送人民检察院审查起诉。 本案中，公安机关将许某的录像设备及录像带拍成了照片，这些照片( )。

A．是物证

B．是书证

C．是原始证据

D．是传来证据