D. where life have developed

　　3. The underlined words "get to the bottom of" in Paragraph 4 probably mean "________".

　　A. understand fully B. make full use of

　　C. search for D. do more research on

　　4. From the passage we can learn ________.

　　A. an Earth­like planet has been found

　　B. it's been proved we are not alone in the universe

　　C. Jose Funes has found the meaning of the human race in the universe

　　D. the discovery of an Earth­like planet could happen in the near future

　　B

　　Elon Musk says Space X is developing a plan for trips to Mars (火星) that will eventually cost just $500,000 per seat. Musk founded Space X 10 years ago and space travel has always been one of his goals for the company. Few details were provided about the Martian voyage, but Musk did say we can expect to hear more about the plan in less than a year.

　　The price for a trip to Mars also highlights (突出) Musk's main effort behind Space X, to bring down the cost of delivering a human into space. In an interview with the BBC, Musk admitted that the first seats won't be selling for $500,000. It will take a while to get down to that price. But Musk says the half­million dollar ticket could happen a decade after trips begin. "Land on Mars, a roundtrip ticket - half a million dollars. It can be done，" he told the BBC.

　　Musk did say that one of the keys to low­cost trips to the red planet would be the ability to not only fuel there, but also to reuse the entire spaceship on the return trip. In the BBC interview Musk said by reusing the spaceship, you end up with the same sorts of costs airlines face. Musk compared it to flying today where a 747 isn't simply thrown away after a flight to London. Like the airplane, the cost of the spaceship could be spread out over many flights rather than just a single trip. The $500,000 price is around one percent of the cost NASA is now paying to send a person to the space station on a Russian rocket.

　　The talk of Martian travel came with Space X's most recent development news of its Dragon capsule. As the California company prepares to send a Dragon to the International Space Station next month, it completed the first crew trial with NASA. The event gave NASA astronauts a chance to test out the 7­seat capsule that is being developed to carry human passengers as well as goods.

　　5. According to the passage, Elon Musk ________.

　　A. will go to Mars at the cost of $500,000

　　B. is the leader of the Space X company

　　C. is an American astronaut from NASA

　　D. will send people to Mars in less than a year

6. What makes the trip to Mars at such a low cost possible?