Almost everybody in America will spend a part of his or her life behind a shopping cart（购物手推车）. They will, in a lifetime, push the chrome-plated contraptions many miles. But few will know—or even think to ask—who it was that invented them.
Sylvan N. Goldman invented the shopping cart in 1937. At that time he was in the supermarket business. Every day he would see shoppers lugging（吃力地携带） groceries around in baskets they had to carry.
One day Goldman suddenly had the idea of putting baskets on wheels. The wheeled baskets would make shopping much easier for his customers, and would help to attract more business.
On June 4, 1937, Goldman’s first carts were ready for use in his market. He was terribly excited on the morning of that day as customers began arriving. He couldn’t wait to see them using his invention.
But Goldman was disappointed. Most shoppers gave the carts a long look, but hardly anybody would give them a try.
After a while, Goldman decided to ask customers why they weren’t using his carts. “Don’t you think this arm is strong enough to carry a shopping basket?” one shopper replied.
But Goldman wasn’t beaten yet. He knew his carts would be a great success if only he could persuade people to give them a try. To this end, Goldman hired a group of people to push carts around his market and pretend they were shopping! Seeing this, the real customers gradually began copying the phony（假冒的） customers.
As Goldman had hoped, the carts were soon attracting larger and larger numbers of customers to his market. But not only did more people come—those who came bought more. With larger, easier-to-handle baskets, customers unconsciously bought a greater number of items than before.
Today’s shopping carts are five times larger than Goldman’s original model. Perhaps that’s one reason Americans today spend more than five times as much money on food each year as they did before 1937—before the coming of the shopping cart.
The underlined words “chrome-plate contraptions” in Paragraph 1 refer to ______.（within 3 words）
_____________________________________________________________________________
What was the purpose of Goldman’s invention? （within 10 words）
_____________________________________________________________________________  
Why was Goldman disappointed at first? （within 10 words）
______________________________________________________________________________
Why did Goldman hire people to push carts around his market? （within 10 words）
______________________________________________________________________________
What is the main idea of this article? （within 10 words）
______________________________________________________________________________