Which paragraph contains the above information? [仅填数字] Fill in the blanks with the corresponding paragraph numbers. 1. Industrial revolution further shrank the world in the 19th century, and made the United States the world's center. 2. In the 1970s, American workers were 20 times as productive as Chinese, but now China is the world’s second-biggest economy. 3. By 2000, China was gaining on the United States; by 2050, it may well displace it. 4. The force driving the rise of the East is exactly the same as the force that drove the earlier rise of the West. 5. There is much that 21st-century Westerners can do to manage the rise of the East.