Guide: Feel free to ask me anything on today's Great Wall tour.
Tourist 1: How long is the wall?
Guide: Ah, the most popular question! If we're only talking about the parts from the Ming Dynasty, it's about 8,850 kilometers long. This makes it the longest wall in the world.
Tourist 2: Wow, that's amazing! Why did the ancient emperors build the wall?
Guide: The main reason was to protect their part of the country. As you can see, it's quite tall and wide. As far as I know, there are no man-made objects as big as this.
Tourist 3: Is Badaling part of the Ming Great Wall?
Guide: Yes, it's the most famous part.
wallamazingancientprotectwidefeel freeas far as I know
形容词最高级
the longest wall in the world（世界上最长的墙）、the most popular question（最热门的问题）。本单元核心语法：形容词和副词的最高级。规则构成：the + 形容词最高级。
as far as I know
As far as I know, there are no man-made objects as big as this.（据我所知，没有任何人造物体有这么大。）as far as I know = 据我所知，口语常用。
要点摘要
导游介绍长城：明代部分8850公里世界最长墙；古人修建为了护疆；八达岭最著名。
Section A 3a (Reading)
Qomolangma — the Most Dangerous Mountain in the World?
珠穆朗玛——世界上最危险的山？
One of the world's most dangerous sports is mountain climbing, and one of the most popular places for this is the Himalayas. The Himalayas run along the southwestern part of China. Of all the mountains, Qomolangma rises the highest and is the most famous. It is 8,848.86 meters high and so is very dangerous to climb. Thick clouds cover the top and snow can fall very hard. Even more serious difficulties include freezing weather conditions and heavy storms. It is also very hard to take in air as you get near the top.
One of the world's most dangerous sports（世界上最危险的运动之一）多音节形容词最高级：the most + 形容词。One of + 最高级 + 名词复数。
take in 吸入
It is also very hard to take in air.（也很难吸入空气。）take in = 吸入（空气/信息）。
Why do so many climbers risk their lives? One of the main reasons is because people want to challenge themselves in the face of difficulties. The spirit of these climbers shows us that we should never give up trying to achieve our dreams. It also shows that humans can sometimes be stronger than the forces of nature.
challengeforcenaturesucceedin the face ofachieve one's dreamforces of nature
in the face of 短语
challenge themselves in the face of difficulties（在困难面前挑战自己）in the face of = 面对。
比较级表示最高级
humans can sometimes be stronger than the forces of nature（人类有时能比自然力量更强大）比较级与最高级的转换。
要点摘要
第一段：珠峰——8848.86米世界最高，攀登极危险：浓云、大雪、极冷、暴风、缺氧。
第二段：攀登者动机——挑战自我、实现梦想。登山精神：人类有时比自然力量更强大。
Section B 2b (Reading)
Pandas — China's National Treasure
熊猫——中国的国宝
It is 8:30 a.m. at the Chengdu Research Base. Panda keepers are preparing milk for the baby pandas' breakfast. At 9:00 a.m., they find that most of the babies are already awake and hungry. When the babies see the keepers, they run over to them with excitement and some of the young pandas even walk into their friends and fall over!
run over to them with excitement（兴奋地跑向他们）with + 抽象名词 = 副词短语，表方式。
Lin Wei, one of the panda keepers, says, "They're so cute and lovely. I take care of them like they're my own babies. I wash, feed and play with them every day. They're very special to me." In fact, many people around the world love these black and white animals. Pandas have become so popular that they are now a symbol of China.
Lin Wei，熊猫饲养员之一，说：「它们太可爱了。我像照顾自己的宝宝一样照顾它们。我每天给它们洗澡、喂食、和它们玩。它们对我来说非常特别。」事实上，全世界很多人爱这些黑白动物。熊猫如此受欢迎，以至于现在它们成了中国的象征。
symboltake care of
so...that... 结果状语从句
Pandas have become so popular that they are now a symbol of China.（熊猫如此受欢迎以至于成了中国的象征。）so + 形容词 + that 从句。
An adult panda weighs many times more than a baby panda. At birth, it's only around 0.1 to 0.2 kilos. At Chengdu, scientists are doing research to better understand the habits of pandas. They also want to find ways to protect pandas and increase the panda population.