The general incidence of colds continues to decline into maturity. Elderly people who are in good health have as few as one or two colds annually. One exception is found among people in their twenties, especially women, who show a rise in cold infections, because people in this age group are most likely to have young children. Adults who delay having children until their thirties and forties experience the same sudden increase in cold infections.
The study also found that economics plays an important role. As income increases, the frequency at which colds are reported in the family decreases. Families with the lowest income suffer about a third more colds than families at the upper end. Lower income generally forces people to live in more cramped quarters than those typically occupied by wealthier people, and crowding increases the opportunities for the cold virus to travel from person to person. Low income may also adversely influence diet. The degree to which poor nutrition affects susceptibility to colds is not yet clearly established, but an inadequate diet is suspected of lowering resistance generally.
The paragraph before this passage most probably deals with ______ .
A.minor diseases other than colds
B.the recommended treatment of colds
C.a factor that affects susceptibility to colds
D.methods of preventing colds among elderly people
第1题
下面有关视频获取设备的叙述中,错误的是()。
A.电视接收卡的主要功能是接收标准的电视信号,并直接将模拟视频信号输出到显示器上
B.视频采集卡将放像机、影碟机等输入的模拟视频信号经过取样、量化以后转换为数字视频输入到主机中
C.数字摄像头通过镜头采集视频图像,转换成数字信号后输入到主机中
D.数字摄像机对拍摄的视频图像进行压缩编码,并记录在存储介质上
第2题
下面有关视频获取设备的叙述中,错误的是
A.电视接受卡的主要功能是接受标准的电视信号,并直接将模拟视频信号输出到显示器上
B.视频采集卡将放像机、影碟机等输入的模拟视频信号经过取样、量化以后转换为数字视频输入到主机中
C.数字摄像头通过镜头采集视频图像,转换成数字信号后输入到主机中
D.数字摄像机对拍摄的视频图像进行压缩编码,并记录在存储介质上
第3题
A.视频卡能通过有线电视电缆接收电视信号并进行数字化
B.数字摄像头必须通过视频卡与PC相连接
C.视频卡一般插在PC的PCI插槽内
D.数字摄像机拍摄的数字视频可通过USB或IEEE1394接口直接输入计算机
第4题
下面关于视频卡叙述不正确的是______。
A.视频采集卡将模拟视频信号经过取样、量化后转为数字图像输入存入到系统主存储器
B.视频捕捉卡一般以PCI接口为主
C.电视接收卡主要原理类似电视机,外置式电视卡可以直接独立工作,驱动显示器
D.多功能视频卡将视频压缩卡和电视接收卡集合于一身,功能强大
第5题
A.视频采集卡的基本功能是将模拟视频信号取样、量化并转换为数字图像输入到主机
B.实时视频压缩/解压缩卡除了能进行视频采集以外,还有专门的处理芯片对采集的视频数据进行实时压缩/解压缩处理
C.电视接收卡中有电视信号的接收、调谐电路,故能在PC显示器上收看电视节目
D.目前PC一般都配有视频采集卡
第6题
A.视频采集卡的基本功能是将模拟视频信号取样、量化并转换为数字图像输入到主机
B.实时视频压缩/解压缩卡除了能进行视频采集以外,还有专门的处理芯片采集的视频数据进行实时压缩/解压缩处理
C.电视接收卡中有电视信号的接收、调谐电路,故能在PC机显示器上收看电视节目
D.目前PC机一般都配有视频采集卡
第7题
视频卡的种类较多,在下列有关各种视频卡的功能说明中,错误的是()。
A.视频采集卡的基本功能是将模拟视频信号取样,量化并转换为数字图像输入到主机
B.实时视频压缩/解压缩除了能进行视频采集以外,还有专门的处理芯片对采集的视频数据进行实时压缩/解压缩处理
C.电视接收卡中有电视信号的接收,调协电路,故能在PC机显示器上收看电视节目
D.目前PC机一般都配有视频采集卡
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