Humans have spent billions of dollars     1    (try) to figure out how to get to Mars. Why do we want to go there so     2    (bad)?

Well, different organizations have different reasons.

Dutch organization Mars One wants to put people on Mars by 2027. They say it is just the next step in human curiosity. “Why did Columbus travel west? Why did Marco Polo head east? Because it is that pull, that unknown, or that chance of adventure    3     makes humans look for new places to explore,” their website says.

Wealthy businessman Elon Musk runs a company in the United States. Its name is SpaceX. One of its main goals is to send humans to other planets, including Mars.

Musk was born in South Africa but is now     4     US-Canadian citizen. He agrees that curiosity plays a part in exploring space. But his main reason     5     wanting to go to Mars is to ensure human     6    (survive). He says that for humans to survive in the future, we must learn     7    (live) somewhere other than Earth.

China has dreams of reaching Mars too. In 2011, along with Russia, they tried to send a probe (探测器) to the planet. Another probe     8    (send) next year.

NASA is also    9    (excite) to put humans on Mars. It says going to Mars will help humans learn much more about the universe. “Future exploration could find evidence of life, answering one of the     10    (big) mysteries of the universe: Does life exist beyond Earth?” the NASA website says.

NASA says Mars and Earth are very alike. Exploring Mars can help us learn more about our own planet’s history and future.

Before the mid-2th century,     1     (travel) into space was an impossible dream. However, some scientists were     2     (determine) to help humans realise their dream to explore space. The USSR focused     3     sending people into space after 4 October, 1957. Though the terrible disasters made people sad and     4     (disappoint), people never gave up     5     (explore) space exploration. This is     6     they believe in the importance of space exploration. China has become the third country in the world to     7     (independent) send humans into space in 2003. Europe, the US and China all have plans to     8     (far) study and explore planets. Despite the     9     (difficulty), scientists hope futher discoveries will enable us     10     (understand) how the universe began and help us survive well into the future.

In the last seven days I have seen the pressure that the NHS is under. I have seen the personal courage not just of the doctors and nurses but of everyone, the cleaners, the       1    (cook), the health care workers of every description-physios, radiographers     2    have kept coming to work, kept putting themselves in harm's way, kept     3    (risk) this deadly virus. It is thanks to that courage, that devotion, that duty and that love that our NHS has been unbeatable.

The Arctic Ocean in summer will very likely be ice free before 2050, at least temporally. The research team     4       (analyze) recent results from 40 different climate models. Using these models, the researchers considered the future evolution of Arctic sea ice cover in a scenario with high future CO2 emissions and little climate protection. As     5    (expect), Arctic sea ice disappeared quickly in summer in these simulations.

However, the new study finds that Arctic summer sea ice also disappears occasionally if CO2 emissions are       6    (rapid) reduced.

In order to understand    7     bird brains changed, a team of 37 scientists used CT scan data to create endocasts(内腔)of hundreds of birds and dinosaurs, which the    8    (combine)with a large existing database of brain measurements from modern birds.

They then analyzed brain-body allometry (体形变). “There is no clear line     9    the brains of advanced dinosaurs and primitive birds,”    10    (note) co-author Dr. Amy Balanoff of Johns Hopkins University." Birds like pigeons have the same brains sizes you would expect for a dinosaur of the same body size, and in fact some species like moa(恐鸟) have smaller-than-expected brains.”

The passage is about a letter    1     (write) by LiQiang who is taking    2    the prize that he won last year. At first he was nervous and     3     (certain) about the journey. However, with WangPing’s guiding, LiQiang was transported into the future     4    (safe). Hit by a lack of fresh air, his head ached and he tried to make the necessary adjustment to this new situation. Soon he was back     5    his feet again and flew after WangPing in a hovering carriage     6    (drive) by computer. Arriving at WangPing’s house, LiQiang was shown into    7    large room made of trees,     8    leaves provided the room with oxygen.     9    (exhaust), LiQiang slid into bed and only then     10    he fall fast asleep.