1,There are many mysteries in nature.自然界有许多神秘的东西
2,Mysteries are things we don't understand, such as how the Egyptian pyramids were built.神秘是我们无法理解的事情，比如埃及金字塔是如何建造的。
3,In fact, we are surrounded by mysteries.事实上，我们被神秘包围着
4,What we know about the world seems like very little.我们对这个世界的了解似乎很少
5,Scientists tell us that what we see in the universe is only a small part of what is there.科学家告诉我们，我们在宇宙中看到的只是宇宙中的一小部分
6,The rest is invisible，including dark matter and dark energy.其余的是看不见的，包括暗物质和暗能量。
7,These two unknowns make up around 95% of the universe.这两个未知数约占宇宙的95%。
8,Evidence for their existence comes from their effects on what we can observe, such as the motion and positions of distant galaxies.它们存在的证据来自它们对我们所能观察到的东西的影响，例如遥远星系的运动和位置。
10、Yet, though we know very little, we are able to build airplanes and communicate with smartphones.然而，尽管我们知之甚少，但我们能够建造飞机和智能手机通信。
11,In some ways we humans are very smart, or at least we think we are.在某些方面，我们人类非常聪明，或者至少我们认为我们很聪明。
12,We still need to face big issues, like climate change, and that is going to be a huge challenge.我们仍然需要面对像气候变化这样的大问题，这将是一个巨大的挑战
13,The challenge for humans will be our ability to adapt to our changing environment.人类面临的挑战将是我们适应不断变化的环境的能力。
14，What about other forms of life?那么其他形式的生命呢?
15,How do they adapt?它们是如何适应的？
16,Seasonal variations, for example, can be one of the greatest challenges for animals to overcome.例如，季节性变化可能是动物克服的最大挑战之一。
17,Overcoming such challenges is a great achievement, but hardly easy.克服这些挑战是一项伟大的成就，但并非易事。
18,Some birds migrate thousands of kilometers each year to deal with seasonal changes.一些鸟类每年迁徙数千公里以应对季节变化。
19,These migrations are amazing.这些迁徙是惊人的
20,Birds don't carry maps or compasses, yet they know where to go.鸟类不带地图或指南针，但它们知道去哪里。
21,They have developed the ability to see the Earth's magnetic field.他们已经发展了观测地球磁场的能力
22,This ability is a wonder of nature.这种能力是大自然的奇迹
23,It takes advantage of the fact that the earth is like a huge bar magnet.它利用了这样一个事实：地球就像一个巨大的磁棒
24,It has a north pole, which is positive, and a south pole, which is negative.它有一个北极，它是正的，还有一个南极，它是负的。
25,Somehow the birds are able to see this magnetic field and use it to their advantage.不知怎的，这些鸟能够看到磁场，并利用它来获取它们的优势。
26,And even the way birds fly together is amazing.甚至连鸟儿一起飞翔的方式都令人惊叹。
27,Many migrating birds fly in a V formation.许多候鸟以V字形飞行。
28,They do this to conserve energy.他们这样做是为了保存体力。
29,In a V formation, birds can use the energy of the birds in front of them.在V形队形中，鸟类可以利用前方鸟类的能量。
30,This energy comes from the air currents generated by the wings.这种能量来自于由翅膀产生的气流。
31,Conserving energy is necessary for the birds to survive the long journey.节约能源对鸟类在长途旅行中生存是必要的
32,How do the birds know this?鸟是怎么知道的？
33,It's truly amazing how the birds know this.鸟类是如何知道这一点的真的很神奇。
