A、Challenges from abroad. B、Lack of constant upgrading. C、Competition of the same trade. D、Some countries’ slowing economies. D录

How long have you had your Apple iPhone or computer? If you have not replaced that product in the last two or three years, you may be part of the reason for Apple’s falling sales numbers.
    Apple is the world’s most valuable company. Sales of Apple products grew every year for 51 straight quarters. That all changed on Tuesday, when the company reported a drop in sales. Sales for the first quarter of this year dropped 13 percent. Sales dropped to $50.6 billion from $58 billion during the same quarter in last year. [16]The news caused Apple’s stock to drop, too. The company’s shares were down by about 8 percent in after-hours trading.
    Some experts say the struggling Chinese economy may be to blame for Apple’s weaker sales. The company’s report shows sales were down in China, Taiwan and Hong Kong by a combined 26 percent. In the past, Apple was able to depend on sales growth in those markets. [17]Apple’s Chief Executive, Tim Cook, says the smartphone market is not growing because of the slowing economies in some countries.
    [18]But other experts say Apple is no longer regularly producing exciting products. People who bought new Apple laptops or smartphones in the last two or three years do not feel like they need to buy the latest products. Rob Pegoraro is a technology writer for USA Today and Yahoo. He says he still likes to use the Apple products he owns but, there is nothing "revolutionary" right now. "You got a lot of people upgrading to the iPhone 6 and the iPhone 6 plus. The 6s and the 6s Plus are better, but as the names would suggest, they’re not exactly revolutionary. Normal people don’t buy new phones every year."
    Pegoraro also says that Apple did not really have a bad quarter. The company still makes a lot of money from the products it sells. It is just not growing anymore. "Their gross margin was 39.4 percent compared to 40.8 percent. I struggle to think of how many other industries or companies could pull down those kinds of profit margins for over a decade straight" Pegoraro warns not to underestimate Apple just because of this small drop in sales. [19]"This company’s problem is that they made a lot of money, just not more money than they made the last quarter. You know, if that’s failure, then I should only hope to be just as much of a disaster!"
16. What is the result of Apple’s falling sales?
17. According to Tim Cook, what is the reason for smartphone’s falling sales?
18. Why do some people think they needn’t buy the latest Apple products?
19. In Rob Pegoraro’s view, what is Apple’s problem?