Who would have believed it？ After what seems like an eternity of tantalizing hype about "h

igh-definition" television, the first digital sets are actually on their way to the market. This much anticipated debut would seem to be terrific news for tube lovers. As promised, the sets deliver super-sharp digital pictures, wide-format movie-style. screens and magnificent stereo surround sound.

So should everybody rush out to buy one？ Well...maybe not. HDTV's obvious advantages over conventional sets are offset by significant disadvantages. For openers, there's the price tag. Sony's small set, with a 34-in screen, lists for a fairly large $8,999. Prices will eventually drop, of course, but Bill Mannion, general manager of Panasonic's TV division, acknowledges, "It's going to be a while, maybe years before most consumers can afford HDTV."

Even if you're a gadget freak with deep pockets, you may think twice about buying for another reason: "high definition" will not be equally high. Some programs will be broadcast at 480 lines of resolution (compared with 330 or so on conventional televisions), others at a sharper 720 lines, and still others at the maximum of 1,080. NBC says it plans to start by offering 480-line quality for day-time programming and 1,080 for some prime-time shows and specials.

But cable-TV customers—a full two-thirds of American households—may get a sinking feeling of another sort if they try to tune in. Cable companies are refusing, for now, to carry broadcasters' HDTV signals, saying information-rich HDTV channels overtax their systems. Therefore viewers, who want decent reception, will have to buy clumsy, old-fashioned TV antennas if they plan to pull in digital broadcasts.

One decision consumers won't have to make is whether to buy a set that uses one format or another. Back in the days when VCRs were new, you could buy a VHS or a Beta-format machine; neither could read or record on the other's tapes. Those who chose Beta generally regretted it, as VHS took over the market, video companies stopped releasing Beta-format movies, and Beta sets became essentially useless.

Most reassuring of all, the new sets will be able to pick up conventional TV broadcasts. You won't need two TV sets sitting side by side. Will that be enough to talk consumers into putting down the better part of $10,0007 Manufactures hope that wide-eyed excitement over this genuinely revolutionary new technology will help hide the fact that it's still a work in progress. Realistically, they expect the revolution to be a slow one.

According to the text, HDTV

A．has its limitations.

B．is a landmark in TV technology.

C．is likely to be accepted by the mass.

D．is doubted by manufacturers on its practicability.