Since astronomers confirmed the presence of planets beyond our solar system, called exoplanets, humans     1     (wonder) how many could harbor life.

Now, we're one step closer to       2    (find) an answer. According to the Kepler space telescope, about half the stars similar in temperature       3    our Sun could have a rocky planet capable of supporting liquid water on its surface.

Our galaxy holds at least an     4    (estimate) 300 million of these potentially habitable worlds, based on even the most conservative interpretation of the results in a new study to be published in The Astronomical Journal.

This research helps us understand the potential for these planets     5    (support) life. This is an essential part of astrobiology, the study of life's origins and future in our universe.

The study is authored by NASA scientists     6    worked on the Kepler mission alongside collaborators from around the world. NASA retired the space telescope in 2018 after it ran out of fuel. Nine years of the telescope's observations revealed that there are billions of planets in our galaxy - more planets than stars.

    7     this result is far from a final value, it’s extremely exciting that we calculated that these worlds are this common with such high confidence.

That's a wide range of different stars, each with       8    own particular properties impacting whether the rocky planets in its orbit are capable of supporting liquid water. These complexities are partly why it is so difficult to calculate how many potentially habitable planets are out there, especially when even our     9    (powerful) telescopes can just barely detect these small planets. That's     10     the research team took a new approach.

A small device, Moxie, has produced oxygen on the surface of Mars,    1     (bring) the chances of surviving on the red planet a step closer. Research published in     2     journal Science Advances reported that Moxie produced breathable oxygen in seven-hour-long tests conducted in various weather and atmospheric conditions last year. The research also found that even in       3    (extreme) harsh weather conditions like a Martian dust storm, Moxie     4    (continue) to produce high purity oxygen.

“This is the first demonstration of actually using     5    (resource) on the surface of Mars and transforming them chemically into something useful for a human mission,” Jeffrey Hoffman, a retired astronaut, said.

“The thin atmosphere on Mars is 96 percent carbon dioxide and much more     6    (change)than on Earth and the temperature can vary by 100 degrees, ” Hoffman said. “One aim is     7    (show) we can run Moxie in all seasons.”

The device, Moxie, uses some special pumps,     8     take in carbon dioxide. The gas     9    (heat) to 800°C and pressed to separate the carbon and oxygen. Carbon monoxide is sent out as waste while the pure oxygen is left behind.

Despite the challenges, Moxie has proved durable in the extreme conditions on Mars and scientists regard the test results     10     a great achievement.

Wang Yaping has become the first Chinese woman     1    (perform) a spacewalk. Wang’s dream of becoming an astronaut was inspired by Yang Liwei’s 2003 space flight. “Now China has its first man in space. When will our country have its first woman?” thought Wang,     2     (work) then as a fighter pilot.     3     (bear) in a small village in Yantai, Shandong Province in 1980, Wang has been     4     (active) participating in long-distance running since primary school. In 1997, Wang, a high school student,     5     (encourage) to apply for the pilot recruitment (征募) program by her classmates. Given her strong build and ability to stay calm under pressure, Wang passed all tests.

In 2010, Wang became an astronaut. However, the joy of     6     (select) did not last long as the cruel training began. In the first year, Wang could not get the top level in the high-G training, during     7     she had to stand eight times the force of gravity. Wang improved her performance by doing extra     8     (strong) exercises every day. At last, Wang realized her space dream in 2013 as part of the Shenzhou-10 mission. During her mission, Wang taught China’s first live physics lesson from space. In 2020,     9     team of Chinese university students majoring     10     aerospace, art, architecture and music translated cosmic (宇宙的) rays into music. They said they had watched Wang’s live space lecture when they were teenagers.

During the next few months, Wang and her teammates will carry out scientific experiments and do spacewalks. Wang is confident that they will complete this mission successfully.