1 . Since Tesla founder Elon Musk published his White Paper On The Fifth Mode of Transportation in 2013, the concept of “Hyperloop” has caught the imaginations of engineers and investors across the world. Simply put, it is just an idea that vehicles filled with passengers or goods are sent through a nearly airless pipe at airliner-speeds of up to 1,223 kilometers per hour.

Critics(批评者) say Hyperloop may only amounts to a pipe dream that would be technically and financially impossible to achieve.

They argue that there are too many safety questions that need to be answered. What if the airless tube breaks? What if the train somehow crashes through the tube? What if earthquakes occur? Such events will be extremely difficult, if not impossible, to be engineered into the system, especially when a vehicle runs at such high speeds in a hundreds-of-miles-long airless tube.

Turning will also be extremely difficult for the high-speed hyperloop. They say that a hyperloop vehicle would need approximately 10 kilometers for a 90-degree turn at 965 kilometers per hour. This may determine how useful the hyperloop can be.

It's still unclear how much it would cost to build a hyperloop, but surely it would be in the billions of dollars. Financial documents leaked from Virgin Hyperloop in 2016 suggested its Hyperloop One would cost between $ 135 million and $ 193 million per kilometer ---significantly more than high-speed rail. Even with public funding, the ticket prices will be unacceptably high for passengers.

Last week, Virgin Hyperloop, one of the leading companies devoted to realizing Elon Musk's pipe dream, announced that for the first time it has conducted a test of its Hyperloop One with human passengers and set a new speed record; 386 kilometers per hour. It is aiming to hit 643 kilometers per hour for the next run.

“Hyperloop One wouldn't have existed unless we put it here. It is going to be that spot where the public can look and say, ‘that was a really big idea,’” said Giegel, co-founder of Virgin Hyperloop, “’but they came, they did it, and they made it a reality.’”

1. What can we know about “Hyperloop”?

A．It is a high-speed car designed by Elon Musk's Tesla.

B．It is a new idea for the next generation transportation.

C．It is a passenger train running in an airless pipe at high speed.

D．It is a spaceship running at a speed of 1,223 kilometers per hour.

2. What do the critics think might be achieved concerning Hyperloop?

A．Its safety.	B．Its speed.
C．Its low building costs.	D．Its cheap ticket prices.

3. How fast did Hyperloop One run during the test last week?

A．386 kilometers per hour.	B．643 kilometers per hour.
C．965 kilometers per hour.	D．1, 223 kilometers per hour.

4. What does the underlined “they” in the last paragraph refer to?

A．Human passengers on Hyperloop One	B．The ordinary people.
C．Virgin Hyperloop founders and engineers.	D．Visitors at Virgin Hyperloop.