New observations of mud cracks made by the Curiosity rover show that high-frequency， wet-dry cycling occurred in early Martian surface environments， indicating that the red planet may have once seen seasonal weather patterns or even flash floods.

“These exciting observations of mature mud cracks are allowing us to fill in some of the missing history of water on Mars. How did Mars go from a warm， wet planet to the cold， dry place we know today？ These mud cracks show us that transitional time， when liquid water was less abundant but still active on the Martian surface，” said Nina Lanza， the lead investigator of the ChemCam instrument onboard the Curiosity rover.

After years of exploring land， the rover entered a new area filled with sulfates（硫酸鹽）， marking a major environment transition. In this new environment， the research team found a change in mud crack patterns， signifying a change in the way the surface would have dried. This indicates that water was still present on the surface of Mars occasionally; meaning water could have been present for a time， evaporated， and repeated until mud cracks formed. Additionally， the rover found evidence that the mud cracks were only a few centimeters deep， which could mean that wet-dry cycles were seasonal， or may have even occurred more quickly， such as in a flash flood.

These findings could mean that Mars once had an Earth-like wet climate， with seasonal or short-term flooding， and that Mars may have been able to support life at some point. “What’s important about this phenomenon is that it’s the perfect place for the formation of polymeric molecules required for life， including proteins， if the right organic molecules were present at this location，” another researcher said， “Wet periods bring molecules together while dry periods drive reactions to form polymers（聚合物）. When these processes occur repeatedly at the same location， the chance increases that more complex molecules formed there.”

（材料選自Science Daily網(wǎng)站，有刪改）

1. What can we know from Nina Lanza’s words？

A. Mars had been a warm， wet planet.

B. The Martian surface has abundant liquid water.

C. Nina can show lead investigators the transitional time.

D. Nina has filled in the missing history of water on Mars.

2. What is the main idea of the third paragraph？

A. The formation of the rover.

B. The new finding of the researchers.

C. The exploration of the rover.

D. The new transition of the researchers.

3. What may be the consequence of Earth-like wet climate in Mar？

A. Flash flood. B. Protein’s variety.

C. Life formation. D. Molecules’ Complexity.

4. In which section of a website may this text appear？

A. Health. B. Science.

C. Education. " "D. Entertainment.

1. A。解析：細(xì)節(jié)理解題。材料第二段的第二句提到“火星是如何從一個溫暖潮濕的星球發(fā)展成今天我們所知的寒冷干燥的地方的呢？”。由此可知，之前的火星是一個溫暖而潮濕的星球。A選項與材料內(nèi)容相符，故選A。

2. B。解析：主旨大意題。材料第三段的第二句提到“研究團隊發(fā)現(xiàn)泥漿裂縫模式發(fā)生了變化”，第四句提到“此外，火星車發(fā)現(xiàn)的證據(jù)表明泥縫只有幾厘米深”。由此可知，材料第三段主要講述的是研究團隊的新發(fā)現(xiàn)。B選項與材料內(nèi)容相符，故選B。

3. C。解析：推理判斷題。材料最后一段的第一句提到“這些發(fā)現(xiàn)可能意味著火星曾經(jīng)有過類似地球的潮濕氣候，有季節(jié)性或短期的洪水泛濫，火星可能在某個時候能夠維持生命”。由此可知，如果火星有像地球一樣的潮濕氣候，那么火星可能在某個時候能夠維持生命。C選項與材料內(nèi)容相符，故選C。

4. B。解析：推理判斷題。通讀整篇材料，我們可知材料介紹的是科學(xué)家通過觀察火星泥漿裂縫，發(fā)現(xiàn)火星之前有可能有類似于地球的四季模式或者是暴洪。這屬于科學(xué)研究的范疇，因此這篇文章最有可能出現(xiàn)在網(wǎng)站的“科學(xué)”版塊。故選B。