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In Dujiangyan, Sichuan Province, a rock wall has offered an extraordinary glimpse into the ancient past—more than 20 fossilized vertebrate footprints have been discovered. According to a preliminary investigation led by Professor Xing Lida, a renowned dinosaur expert from China University of Geosciences, Beijing, these tracks include multiple dinosaur footprints estimated to be around 200 million years old. This is the first discovery of dinosaur track fossils in the region, providing valuable physical evidence to decode early dinosaur evolution and reconstruct prehistoric environments.

The site was accidentally found by a hiker with geological knowledge on November 23. Noticing distinct claw marks and compression textures on a sedimentary rock wall, he reported the unusual markings. Subsequent examination by Professor Xing’s team confirmed the traces come from Upper Triassic strata. The recorded footprints vary in size and fall into three categories: medium and large theropod footprints, small theropod footprints, and Chirotherium-type tracks that resemble a handprint.

The three-toed theropod footprints with sharp claw impressions were left by carnivorous dinosaurs walking on their hind legs. In contrast, the distinctive Chirotherium-type tracks—with their outward-splayed fifth digit—are believed to be from early archosaurs, the primitive reptilian ancestors of dinosaurs. This site is uniquely significant: it is China’s only known Triassic location where both theropod and Chirotherium footprints coexist, suggesting a shared habitat for these creatures.

Furthermore, Professor Xing emphasized the site’s importance. He noted that footprints are preserved across at least four rock layers, indicating dinosaurs lived here for a long period and moved about frequently. Adding to its scientific value, fossilized wood—including fallen logs and upright stumps—was found embedded in the surrounding rock. This provides a rare snapshot of the ecosystem from over 200 million years ago. Researchers believe further study will shed more light on the early spread and evolution of dinosaurs in China.

1.1. What is the significance of the fossil discovery in Dujiangyan?

A It sets a new local discovery record.

B It dates back to 100 million years.

C It has little scientific research value.

D It proves early dinosaur evolution.

解析：选A。1.A 推理判断题。根据第一段中“This is the first discovery of dinosaur track fossils in the region, providing valuable physical evidence to decode early dinosaur evolution”可知，该发现是该地区首次发现的恐龙足迹化石，即创下了当地的新发现记录。B选项“可追溯至1亿年前”与原文“around 200 million years old”不符；C选项“几乎无科学研究价值”与“valuable physical evidence”矛盾；D选项“证明恐龙进化”属于过度推断，原文仅表明其为解码恐龙进化提供证据。故选A。

2.2. Which of the following is TRUE about the initial fossil discovery?

A It resulted from a formal scientific survey.

B The hiker’s professional knowledge helped it.

C Only the largest footprints were initially found.

D The first team visit confirmed all related details.

解析：选B。2.B 细节理解题。根据第二段首句“The site was accidentally found by a hiker with geological knowledge...”可知，这位徒步者的专业知识（geological knowledge）对最初的发现和上报起到了关键作用。A项“通过正式科学调查完成”与原文“偶然发现（accidentally found）”矛盾；C项“最初仅发现最大的足迹”与原文“记录了多种尺寸足迹”不符；D项“首次团队访问确认了所有相关细节”与“后续检查（Subsequent examination）...确认”所描述的逐步验证过程不符。故选B。

3.3. What can we infer about Chirotherium-type tracks?

A They were left by plant-eating dinosaurs.

B They are traces of ancient primitive reptiles.

C They have the same shape as three-toed prints.

D They belong to the same group as theropods.

解析：选B。3.B 推理判断题。根据第三段中“the distinctive Chirotherium-type tracks... are believed to be from early archosaurs, the primitive reptilian ancestors of dinosaurs”可知，这类足迹来自早期主龙类——恐龙的原始爬行动物祖先，由此可推断其是远古原始爬行动物的痕迹。A选项“由食草恐龙留下”原文未提及；C选项“是三趾足迹”和D选项“属于兽脚类恐龙”均是兽脚类恐龙足迹的特征，与该类足迹无关。故选B。

4.4. What does the fossilized wood contribute to the discovery?

A It shows the main food source of dinosaurs.

B It proves dinosaurs’ long-term residence here.

C It reflects the ancient local ecosystem.

D It confirms the exact age of the rock layers.

解析：选C。4.C 细节理解题。根据第四段“fossilized wood... providing a rare snapshot of the ecosystem from over 200 million years ago”可知，化石木材为了解2亿多年前的当地生态系统提供了珍贵缩影。选项C“It reflects the ancient local ecosystem”是对“providing a rare snapshot of the ecosystem”的同义转述。A选项“显示恐龙的主要食物来源”原文未提及，化石木材未明确是恐龙食物；B选项“证明恐龙在此长期栖息”是岩石层中多组足迹的作用，非化石木材的贡献；D选项“确认岩层的确切年代”是研究团队通过地层分析得出的，与化石木材无关。故选C。