2 . The latest research ________ shows that WeChat is the most popular social networking tool among Chinese netizens.

A．to conduct

B．conducted

C．conducting

D．having been conducted

4 . To return to the problem of water pollution, I’d like you to look at a study _________(conduct) in Australia in 2019. (所给词的适当形式填空)

6 . Yangshuo is really beautiful. A study of travelers ________(conduct) by the website TripAdvisor names Yangshuo as one of the top 10 destinations in the world. （所给词的适当形式填空）

7 . Directions: Complete the following passage by using the words in the box. Each word can be used only once. Note that there is one word more than you need.

A. acquired 　　　B. availability 　　　C. conducting 　　　D. dramatically 　　　E. focused F. growing 　　　G. instantly 　　　H. natural 　　　I. pioneering 　　　J. potential 　　　K. readiness

NASA is on a journey to Mars, with a goal of sending humans to the Red Planet in the 2030s. That journey is already well under way.

For decades, the agency and its partners have sent orbiters, landers and rovers（探测器）,     1     increasing our knowledge about the Red Planet and paving the way for future human explorers. The Curiosity rover has gathered radiation data to help us protect future astronauts, and the upcoming Mars 2020 rover will study the     2     of Martian resources, including oxygen.

Building on the robotic legacy（遗产）, the human exploration of Mars crosses three thresholds（门槛）, each with     3     challenges as humans move farther from Earth: Earth Reliant, the Proving Ground, and Earth Independent.

Earth Reliant explorations is     4     on research aboard the International Space Station. The orbiting microgravity laboratory serves as a world - class test bed for the technologies and communications systems needed for human missions to deep space. Astronauts are learning about what it takes to live and work in space for long periods of time, improving our understanding of how the body changes in space and how to protect astronauts' health.

Next, we move into the Proving Ground,     5     a series of missions near the moon called “cislunar space” to test the capabilities we will need to live and work at Mars. Astronauts on the space station are only hours away from Earth, but the proving ground is days away, a(n)     6     stepping stone to a Mars mission, which will be months away from home.

Also in the 2020s, we’ll send astronauts on a year-long mission into this deep space proving ground, confirming habitation and testing our     7     for Mars.

Finally, we become Earth Independent, building on the knowledge     8     on the space station and in deep space to send humans to low-Mars orbit in the early 2030s.

This phase will also test the entry, descent（降落）and landing techniques needed to get to the Martin surface and study what's needed for in-situ resource utilization or "living off the land". NASA is already studying the     9     "Exploration Zones" on Mars that would offer compelling science research and provide resources our astronauts can use.

There are challenges to     10     Mars, but we know they are solvable. We are well on our way to getting there, landing there, and living there.

8 . Fill in the blanks with the proper form of the given expressions.

have a passion for　　　conduct an experiment　　be at a loss leave sth. to sb.　　　brag about　　　at very short notice

1. He likes _________________ his daughter to his relatives and colleagues.
2. He ________________ football, and we can always see him on the playground.
3. The scientists are absorbed in ___________. Don’t interrupt them.
4. When the teacher asked the question, he felt greatly puzzled and __________ how to     answer it.
5. Some actors and actress do 90% of the stunts and the last 10% ______________ stunt   professionals.