问题
单项选择题
用来描述数据传输服务质量的是( )。
A．QoS
B．DNS
C．ATM
D．UDP
答案
参考答案：A
解析： 本题考查数据传输服务质量的表示。DNS是指域名服务；ATM是指异步传输协议；UDP是指用户数据报协议；QoS是Quality of Service的缩写，意思是数据传输的服务质量。故本题选择A。
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用来描述数据传输服务质量的是( )。
A．QoS
B．DNS
C．ATM
D．UDP
参考答案：A
解析： 本题考查数据传输服务质量的表示。DNS是指域名服务；ATM是指异步传输协议；UDP是指用户数据报协议；QoS是Quality of Service的缩写，意思是数据传输的服务质量。故本题选择A。
| 完形填空。 Scientists are trying to make the desert into good land again. They want to bring 1 to the desert, so people can live and grow food. They are 2 a lot about the desert. But 3 of the earth is becoming desert all the time, scientists may not be able to 4 . the deserts. Scientists think that people make deserts. People are doing 5 things to the earth. Some places on the earth don't get 6 . But they still don't become deserts. This is _7 _ some green plants are growing there. Small green plants and grass are very 8 to dry places. Plants don't let the wind blow the earth away. When 9 _ bit of rain falls, the plants hold the water. 10 plants, the land can become a desert much more easily. | |||
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