资料题：According to the passage, Hollywood studios are no longer the heart of the world' s motion picture production because（  ）。

Hollywood suggests glamour, a place where the young starstruck teenagers could, with a bit of luck, fulfill their dreams.Hollywood suggests luxurious houses with vast palm-fringed swimming pools, cocktail bars and furnishings fit for a millionaire.And the big movie stars were millionaires.Many spent their fortunes on yachts, Rolls Royces and diamonds.A few of them lost their glamour quite suddenly and were left with nothing but emptiness and colossal debts.Movies were first made in Hollywood before World War I.The constant sunshine and mild climate of southern California made it an ideal site.for shooting motion pictures.Hollywood's fame and fortune reached its peak in the 1930s and 1940s, the golden days of the black and white movies.Mot' of the famous motion pictures corporations of those days, Metro-Goldwyn-Mayer, Columbia,and Warner Brothers are sill very much in business and great stars like Ingrid Bergman, Humphrey Bogart, Vivian Leigh, Clark Gable, and many others besides, have become immortal.In those days Hollywood was like a magnet, drawing ambitious young men and women from all over the world.Nowhere else in the wold has developed so expertly the skill of advertising as the Hollywood.The Hollywood studios, by means of advertising, turned starlets into superstars.Mary studio chiefs were tyrants, determined to get their own way at all costs, no matter how unscrupulous the means.The stars were held on a tight rein by the studio chiefs who could make and break all but stars with really big appeal.The stars were "persuaded" to sign seven-year contracts, during which time the studio saw to their grooming and packaging.Under their contracts the stars did not have the night to choose their parts.They were often typecast.Their studios decided everything.Hollywood still retains much of its glamour.crowned with such movie hits as"Gandhi","Amadeus" ,"Born on July 4th" ,"Schindler's List" ,"Titanic" along with a galaxy of superstars including Meryl Streep, Dustin Hoffman, Anthony Hopkins, AL Paccino, etc..all of them together add up to a weighty achievement of Hollywood today.In the recession years of 1992, the movie industry in the U.S.ranked among the brightest spots in the country's balance-of-tradespreadsheet, bringing in more than $ 1.7 billion in foreign revenue.The major difference that has occurred to Hollywood studios is that most movies today arefilmed on location, that is to say, in any part of the world that the script demands.The Hollywood studios are still standing, but most of them have been leased to television networks.About 80% of all American TV entertainment comes form Hollywood.Nevertheless, Hollywood is a name which will always be associated with motion picture-making, and for many years to come Hollywood movies will be shown in movie houses and on TV screens all over the world.