英语听力：2013-05-31 完美捕食 Perfect Predators —13
时间：2019-01-23 作者：英语课 分类：探索与发现2013年
英语课
Picture a living plane, and that gives you a sense of what Quetzalcoatlus would look like in life.
And this is an animal that probably accelerates over 2.5G’s just on takeoff.
Just beyond our comprehension.
A Quetzalcoatlus is 10 times the weight of the largest flying bird today. Yet this airborne reptile 1 doesn’t rely on feathers. Its wings are made of skin. Almost half of that wing is supported by an extended finger bone, a finger 2.5 meters long. A second bone lines the front of the wing, forming a leading edge, similar to an aircraft.
This aerodynamic design allows for near-perfect control on takeoff and landing. But for this flying monster, getting off the ground is the hardest task.
Big pterosaur like Quetzalcoatlus giraffe height on all fours, and it’s got to get up into the air. How is it gonna do that?
And that’s made it more difficult living on the plains of Texas.
Flat ground, no hills, no cliffs, no special conditions, nothing to help it at all except its muscles. It could still take off from a standstill without any running required.
The secret to how this Goliath takes off can be seen in a creature 1,000 times smaller, the vampire 2 bat.
They have to spring up into the air. They have to do essentially 3 a super push-up with their powerful forelimbs, the strongest limbs they have, get up high enough so that they can get their wings to flap and get off the ground.
A Quetzalcoatlus takes off in the same way, using all four limbs to suddenly leap up into the air. Its powerful arm muscles are composed of 80% fast-twitch fiber 4, a third more than humans. This specialized 5 muscle tissue is capable of delivering rapid bursts of energy. This energy is needed to propel this creature weighing as much as a grizzly bear, from a dead stop to a launch speed of 50 kilometers…
n.爬行动物；两栖动物
- The frog is not a true reptile.青蛙并非真正的爬行动物。
- So you should not be surprised to see someone keep a reptile as a pet.所以，你不必惊奇有人养了一只爬行动物作为宠物。
n.吸血鬼
- It wasn't a wife waiting there for him but a blood sucking vampire!家里的不是个老婆，而是个吸人血的妖精！
- Children were afraid to go to sleep at night because of the many legends of vampire.由于听过许多有关吸血鬼的传说，孩子们晚上不敢去睡觉。
adv.本质上，实质上，基本上
- Really great men are essentially modest.真正的伟人大都很谦虚。
- She is an essentially selfish person.她本质上是个自私自利的人。
n.纤维，纤维质
- The basic structural unit of yarn is the fiber.纤维是纱的基本结构单元。
- The material must be free of fiber clumps.这种材料必须无纤维块。
adj.专门的，专业化的
- There are many specialized agencies in the United Nations.联合国有许多专门机构。
- These tools are very specialized.这些是专用工具。