我国国有经济在国民经济发展中的主导作用，主要通过下列哪方面体现出来？（）

A.国有资产在社会总资产中的量的优势

B.国有大型企业和企业集团的规模和实力

C.对经济发展的控制力和其市场竞争力

D.国家对市场活动的正确指导和有效调控

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．FTTH

B．HFC

C．FTTC

D．HDSL