［CHINESE］
恐龙是什么
恐龙是生活在距今约2.35亿年至6500万年前的一类陆地爬行动物，分为蜥臀目和鸟臀目两大类。蜥臀目包括兽脚类和蜥脚类，兽脚类都是食肉恐龙，蜥脚类都是植食性恐龙。鸟臀目都是植食性恐龙，分为鸟脚类、剑龙类、甲龙类、角龙类和肿头龙五类。
这个庞大的家族包括了数千个不同的属种，从体长45米的大型草食性恐龙，到只有麻雀大小的微型食肉恐龙，它们支配地球大陆超过了1.6亿年之久。
恐龙足迹和形成
恐龙足迹化石是恐龙在生活时期行走于未完全固化的沉积物表面上而留下来的印迹，在经过岩化作用后而保存下来的化石。它不仅包括恐龙的足迹，行迹等等，通过研究这些痕迹，可以得到诸如恐龙演化、生活习性、行走速度、古环境和古生态等。
恐龙足迹的种类
现在古生物学家可以根据恐龙足迹的轮廓及形状来区分兽脚类、蜥脚类、小型鸟脚类、禽龙类、剑龙类、甲龙类和角龙类等。例如，在延庆地质公园里，兽脚类恐龙足迹通常为三趾型，并有非常尖锐的爪痕；蜥脚类恐龙足迹像大型的圆坑，后足迹还有三个爪痕；禽龙类恐龙后足迹为三趾型，爪痕非常粗。
延庆恐龙足迹的类型和科学意义
恐龙足迹化石是恐龙生活时期留下的恐龙活动的原始证据，它可以提供恐龙的类型、大小、恐龙数量和相对丰度、行走方向和速度、足部形态和脚趾数量等信息。延庆恐龙足迹化石群规模比较大，初步研究表明它包含有大型蜥脚类恐龙、中型蜥脚类、大型和小型兽脚类、小型鸟脚类等几类恐龙的足迹。某些足迹可以反映出有趣的古行为学现象，如行走、奔跑和跳跃等。例如，有一组罕见的极高速奔跑的恐龙足迹表明这头恐龙正处于追捕猎物或拼命逃跑的状态，结合该足迹点穿插于植食性恐龙足迹之间，不能排除当时正发生着一场捕猎。经过对本地区沉积环境的分析表明，远古时代这里是湖泊边缘，正是恐龙的饮水场地。
由于多数含有恐龙足迹化石的岩石中很少有恐龙骨骼化石，因此恐龙足迹在解释恐龙动物群地层、古生态和古生物地理时空分布等方面有着巨大的潜力。
你的任务：
请将以下三个问题的答案发到我的邮箱里，以确保您的log是真实有效的。如果在两个星期内没有收到邮件，我将会删除您的log。
- 从这里发现的大型蜥脚类恐龙足迹推测它的体长大约是多少米？
- 在这里发现的大型兽脚类恐龙足迹长度大约是多少厘米？
- 这处恐龙足迹化石的发现者是谁的团队？
请不要将问题答案写在您的log里，但是您可以上传与恐龙足迹在一起的照片。
这里有一个小停车场，注意来往车辆！
［ENGLISH］
What is dinosaur
Dinosaur is a kind of terrestrial reptile lived from 235 to 65 million years ago，composed of Saurischia and Ornithischia。Saurischia includes the theropod and sauropod，the theropod is meat－eating dinosaur and sauropod is plant－eating。The Ornithischia consists of ornithopoda，stegosauria，ankylosauria and ceratopsia。
Dinosaur has more than one thousand species，which dominated the earth for more than 160 million years。Dinosaur bodies range from 45m－long huge plant－eating one to sparrow－sized meat－eating one。
What is a dinosaur footprint and how to form
A dinosaur footprint is an impression made by a dinosaur foot on unconsolidated sediment surface，indicating the dynamic activity of dinosaurs during life，and then fossilized together with the digenesis of the footprint－bearing sediment。Dinosaur footprint include track，trackway，which can provide rich information on dinosaur living habits，walking or running speed，evolution，paleoecology and paleoenvironment。
The dinosaur footprint can only be preserved on the substrates with suitable grain size，firmess，temperature and exposed time。Besides，the footprint should be covered by overlying sediment in right time （not too earlier or later）。Therefore，every dinosaur footprint is really precious。
Type of dinosaur footprint
Now，paleontologists can distinguish the footprint of theropoda，sauropoda，small－sized ornithopoda，hadrosaur，stegosauria，ankylosauria and ceratopsia。Example，in Yanqing Geopark the theropoda footprint is tridactyl（3-toe） with sharp claw mark；the sauropoda footprint is composed of manus and pes，huge round pit， with three rough claw marks in its pes；the hadrosaur is tridactyl in its pes（hind foot）and its marks are thick and obtuse。
Types and scientific significance of dinosaur footprints in Yanqing Geopark
Dinosaur footprints represent in situ evidence of the dynamic activity of dinosaur during life。It can tell us about approximately dinosaur type，how many animals were present in a particular area，they move，their relative abundance，size and speed，shape of feet，number of toes。There are many dinosaur footprint at the core area of Yanqing Geopark and study indicates these trackmakers belong to large sauropods，medium sized sauropods，small and large theropods and small ornithopods。Some dinosaur footprints in the Yanqing Geopark might indicate some interesting paleoethology，walking，runing，jumping。Example，in there，the rare and high speed theropod track way might imply a hunting activity，which is coincident with the phenomenon that some meat－eating theropod trackways are interwoven in some plant－eating sauropod trackways in this area of Geopark。So we can't rule out that here might be a hunting field for theropods in the ancient time。Primary study shows this place was a lake beach and where was a place for dinosaur drink water。
Due to the common absence of dinosaur skeletal fossils in the footprint－bearing rocks，the dinosaur footprint show a remarkable potential for suggesting temporal and spatial patterns of stratigraphic，paleoecological and paleobiogeographic distribution of dinosaur faunas。
Your task：
Please send the answers of the following three questions to my email address or message to make sure your log is valid. If I did not receive the mail or message within two weeks, I will delete your log。
1. The pes footprints of large sauropod from here found。What body length about on the inference？
2. What is the length of the large theropod footprints in here?
3. Whose team is the discovery of this dinosaur footprint?
Please do not share your answers in your log but you can put on photo with dinosaur footprint.
A micro park in there and be careful traffic!