There are many different cycles in nature, such as the cycle of seasons.在自然界有许多不同的循环，比如季节的循环
A cycle is a series of events that repeat, such as the daily cycle of light and dark.循环是一系列事件的重复，比如日别的白天和黑夜
The time it takes for a cycle to repeat itself is its period.自身循环所花的时间是它的周期
To evolve means to change or improve over a period of time.进化是指一段时间的改变和改善
In biology, the theory of evolution says that advanced life forms such as humans have evolved from lower forms of life.在生物学，进化论 说的是高级的生命形式，比如人类是从生命的低级形式进化
Life forms evolve because they have to adapt in order to survive.生命形式进化因为为了生存它们必须适应
A force of attraction brings two objects closer together, such as the force of gravity.吸引力促使两个物体靠的更近，比如重力
A force of repulsion pushes two objects away from each other, such as the force between two electrons.排斥力把两个物体互相推开，比如两个电子间的力
Gravity is a force of attraction between two objects with mass.重力是两个有质量的物体之间的引力
To transform means to change from one form into another.改变意思是从一种形式变成另一种
A transformation occurs when an object takes on a new appearance or structure.当一个物体呈现一个新的外观和构造时转化发生
Over a period of time，the process of evolution can transform the appearance of a species of life.在一段时间内进化的过程能改变生命的种类的外观
To inherit something means to get it without having to ask or work for it.继承一些东西意思是没有要或工作就可以得到
A child from a very rich family may inherit a lot of money.很富有的家庭的一个小孩可以继承许多钱
Eye and hair color are inherited traits.眼睛和头发的颜色是被遗传的特质
If two people are attracted to each other they want to be together.如果两个人互相有吸引，那么他们想要在一起
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