采用以下扩展名的文件,属于视频文件格式的有 ( ) 。 ① rmvb ② avi 发布时间:2018-07-13 06:16 │ 来源:www.tikuol.com 题型:单项选择题 问题: 采用以下扩展名的文件,属于视频文件格式的有 ( ) 。 ① rmvb ② avi ③ png ④ jpg ⑤ wmvA.①、②和③B.①、②、和④C.①、②和⑤ D.①、②、③和⑤
题型:单项选择题 如图所示,当关闭K时,向A 中充入2molX、7molY,向B中充入4molX、14molY,起始时VA=VB=a升,在相同温度和有催化剂存在的条件下,两容器各自发生下列反应: 2X(g)+2Y(g)Z(g)+2W(g)△H<0达到平衡(Ⅰ)时V(B)=0.9a升,试回答:(1)B中X 的转化率α(X)B为 (2)A中W和B中Z的物质的量的比较: n(W)A n(Z)B(填<、>、或=)(3)打开K,过一段时间重新达平衡(Ⅱ)时, B的体积为 升(用含a的代数式表示,连通管中气体体积不计)(4)要使B容器恢复原来反应前的体积,可采取的措施是 。 查看答案
题型:单项选择题 A typical application of this (71) is ADSL. It is emerging as the technology for home-and small-office Internet connectivity. It provides either 1.5 Mb/s~8 Mb/s from the network to the user and 64 kb/s~512 kb/s in the reverse direction depending on the distance, 12000 or 18000 feet. The different speed for each direction gives it the (72) label. ADSL is designed to take advantage of the fact that video-on demand, telecommuting, and Internet access traffic are inherently asymmetrical. The user (73) a brief message up to the network and receives a ton of data coming back, either a movie or a piece of data download. Under such a scenario, low-speed traffic to the network is just fine. ADSL .delivers high (74) where you need it and only uses a single copper pair. Through multiplexing, it also reserves (75) of the bandwidth for POTS.A.2 kHzB.4 kHzC.16 kHzD.64kHz 查看答案