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China’s unbelievable high-speed rail network
At the beginning of the 21st century China had no high-speed railways. Slow, crowded and often uncomfortable trains ran across this vast country, with low average speeds making journeys such as Shanghai-Beijing a test of travel.
Today, it’s a completely different picture. With 37,900 kilometers of lines, linking all of its major big cities. China has the world’s largest work of high-speed railways. Half of that total has been completed in the last five years alone, with a further 3,700 kilometers due to open in the coming months of 2021. The network is expected to double in length again, to 70,000 kilometers, by 2035.
1．How were the trains in China at the beginning of the 21st century?| A．Fast. | B．Comfortable. | C．Crowded. |
| A．3,700. | B．37,900. | C．70,000. |
同类型试题
y = sin x， x∈R， y∈[–1，1]，周期为2π，函数图像以 x = (π/2) + kπ 为对称轴
y = arcsin x， x∈[–1，1]， y∈[–π/2，π/2]
sin x = 0 ←→ arcsin x = 0
sin x = 1/2 ←→ arcsin x = π/6
sin x = √2/2 ←→ arcsin x = π/4
sin x = 1 ←→ arcsin x = π/2
y = sin x， x∈R， y∈[–1，1]，周期为2π，函数图像以 x = (π/2) + kπ 为对称轴
y = arcsin x， x∈[–1，1]， y∈[–π/2，π/2]
sin x = 0 ←→ arcsin x = 0
sin x = 1/2 ←→ arcsin x = π/6
sin x = √2/2 ←→ arcsin x = π/4
sin x = 1 ←→ arcsin x = π/2
