Simple Machines
美音、自然拼读、分级阅读与词汇复习
There are many kinds of machines.
机器种类多.
Most machines make doing work easier.
多数机器使工作更容易进行.
They do this by reducing how much push or pull is needed to do work.
他们这样做是为了减少工作需要多少推动或拉力。
Some machines are simple.
有些机器很简单
They have very few parts.
它们的部件很少。
They are called simple machines.
它们被称为简单的机器。
A lever is one kind of simple machine.
杠杆是一种简单的机器。
It makes work much easier.
这让工作容易得多。
A bottle opener is a lever.
开瓶器是一种杠杆.
It makes it easier to open a bottle.
更能开一瓶.
A hammer is a lever too.
锤子也是个杠杆
It makes it easier to pound nails into wood.
更能把指甲打入木头
An inclined plane is another kind of simple machine.
倾斜平面是另一种简单的机器.
It makes work much easier.
这让工作容易得多。
The ramp is an inclined plane.
坡道是倾斜平面.
It makes it easier to move things into a truck.
这样可以把东西搬进卡车里
The inclined plane uses less force than lifting things straight up and into the truck.
倾斜的飞机比把东西直接抬到卡车上用得更少。
But with the inclined plane, you have to move things a greater distance.
但用倾斜的平面, 你必须移动的东西更远。
The wedge is a simple machine.
楔形是简单的机器.
It makes work much easier.
这让工作容易得多。
It is really two back-to-back inclined planes.
这真的是两架相继倾斜的飞机。
A knife is an example of a wedge.
取一刀为楔取之例.
It makes it easier to cut things.
更能更方便切取诸事.
A screw is a simple machine, too.
螺钉也是简单的机器
It is an inclined plane wound in a circle.
这是圆形的平面伤口
Screws make it easier to hold things together or move things up or down.
螺丝可以更容易地把东西放在一起或者把东西上下移动.
A jar lid is a kind of screw.
罐盖是一种螺丝.
A pulley is a kind of simple machine.
滑轮是一种简单的机器。
It makes work easier.
这会使工作更容易。
The flagpole has a simple pulley.
旗杆有简单的拉杆.
The pulley makes it easier to raise and lower the flag.
牵引车可以更容易地升起并降低国旗.
Sometimes two or more pulleys are combined.
有时会将两辆或多辆牵引车合并.
They reduce the amount of push or pull needed to do work.
它们减少了工作所需的推力或拉力.
A wheel and axle is another kind of simple machine.
轮轴是另一种简单的机器.
It makes work much easier.
这让工作容易得多。
A doorknob and a steering wheel are wheels and axles.
一个门把手和一个方向盘是轮子和轴.
The doorknob makes it easier to open a door.
门把手能方便开一扇门.
The steering wheel makes it easier to turn a car.
方向盘让车变更方便.
In time, people learned how to combine one or more simple machines.
随着时间的推移,人们学会了如何结合一台或多台简单的机器.
These machines are called compound machines.
这些机器被称为复合机.
A can opener is a compound machine.
开罐器为复合机.
A bulldozer is also a compound machine.
一台推土机也是一台复合机。
It has many moving parts.
它有很多移动的部分。
The can opener has three simple machines.
开罐器有三台简单的机器.
The turning knob on the can opener is a wheel and axle.
开罐器上转动的拐角是轮和轴.
The hinged handles form a lever, and the cutting part is a wedge.
被链柄会形成杠杆,而剪接部分是楔形.
wedge lever wheel and axle
楔式杠杆轮和轴