The greater your distance from sea level, the colder the air around you becomes.翻译

资料：The personal computer was a revolution in information technology that spawned a $50 billion hardware business, with another $30 billion in software and peripherals （eg. mouse, keyboard, printer, etc.） by 1991. During its short 15 years, the industry evolved through three successive periods. During its first 5 to 6 years, it was characterized by explosive growth and multiple, small competitors vying for a piece of the market. From 1981 to 1985, the industry became a battle for standards and retail shelf space. The third era was one of increasing fragmentation. From 1986 through 1991-1992, new manufacturers from around the world grabbed from the industry leaders as new channels of distribution emerged and product innovation as well as revenue growth slowed.
During the early years of the industry, venture capital in the U.S. encouraged the entry of new firms that offered products in every conceivable shape and size. By 1980, new entrants flooded the market, prompting distinct standards and unique technical features. Almost every firm had a different configuration of hardware and software. The first PC had relatively little speed or memory. However, even these early computers allowed managers to perform tasks that were very time consuming.

When did the PC industry start?

A.Around 1981.
B.Around 1986.
C.Around 1976.
D.Around 1992.

The personal computer was a revolution in information technology that spawned a $50 billion hardware business with another $30 billion in software and peripherals (e.g. mouse keyboard printer etc. ) by 199. During its short 15 years the industry evolved through three successive periods. During its first 5 to 6 years it was characterized by explosive growth and multiple small competitors vying for a piece of the market. From 1981 to 1985 the industry became a battle for standards and retail shelf space. The third eras was one of increasing fragmentation. From 1986 through 1991-1992 new manufacturers from around the world granted from the industry leaders as new channels of distribution emerged and product innovation as well as revenue growth slowed
During the early years of the industry venture capital in the U.S. encouraged the entry of new firms that offered products in every conceivable shape and size. By 1980 new entrants flooded the market prompting distinct standards and unique technical features. Almost every firm had a different configuration of hardware and software. The first PC had relatively little speed or memory. However even these earl computers allowed managers to perform tasks that were very time consuming.
When did the PC industry start?

A. Around 1981
B. Around 1966
C. Around 1976
D. Around 1992