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托福听力单项突破练习分享,希望对大家的学习有所帮助。
1. What is the lecture mainly about?
A. Evidence proving that water was once on Mars
B. Scientific analyses currently being done on mineral samples from Mars
C. Recent developments that could help determine whether life ever existed on Mars
D. An approach to determining whether amino acids on Earth originated on Mars
2. What was discovered on Mars that suggests water once existed there?
A. Microorganisms that can form only in the presence of water.
B. A mineral that can form only in the presence of water.
C. Proteins that have the same structure as proteins found on Earth.
D. Large deposits of iron and potassium that can form only in the presence of water.
3. How might jarosite found on Mars differ from jarosite found on Earth?
A. Mars jarosite and Earth jarosite might have been created by different processes.
B. Mars jarosite might have been formed without water.
C. Mars jarosite might not contain as much iron or potassium as Earth jarosite.
D. Mars jarosite might be more acidic than Earth jarosite.
4. According to the professor, what are two important capabilities of the microfabricated organic analyzer? Click on 2 answers
A. It can accurately test for the presence of water.
B. It can analyze soil samples without returning them to Earth.
C. It can return soil samples back to Earth quickly.
D. It can determine the handedness of amino acids.
5. What point does the professor make about the twenty amino acids that occur on proteins on Earth?
A. They can be either right-handed or left-handed.
B. They were synthesized through abiotic processes.
C. They all have a crystalline structure.
D. They are all left-handed.
6. What would a prevalence of right-handed amino acids in mineral samples collected on Mars indicate?
A. That amino acids on Mars probably originated on Earth
B. That amino acids existed on Mars long before they existed on Earth
C. That a type of microorganism may have existed on Mars that is different from any on Earth
D. That left-handed amino acids are probably present in some minerals on Mars