任务型读写。
From the beginning of human history, people have used oils from seeds and nuts.Most of the time
these oils are used as food, especially in cooking.But sometimes they have other uses.For example, oils
are used in paint and in cleaning products like soap.
Oils are separated from seeds by using pressure.A machine called a press is often used.
The first step in pressing the oil from seeds is to crush the seeds between two stones.The crushed
seeds are then put into a cloth bag and the bag is hung up.Some of the oil will flow out of the bag and
can be collected.
But some oils will remain in the crushed seeds inside the bag.The easiest way to get the rest of the oil
out is to place heavy rocks on the crushed material.
Another method is to place several cloth bags on top of each other in a box.Then a long wooden stick
is used to slowly push a heavy cover down on the bags.Great pressure is produced in this way.Much
greater pressure can be produced by using a machine, a hydraulic jack (液压千斤顶). The greater the
pressure is, the more oils will be produced.
Small presses are important in areas where electricity or gasoline cannot be used.They are also a good
way to test if a local market for oils exists.
Small batch presses can be made of local materials.Their cost is low.They are not difficult to operate.
And they are easy to repair.The small presses produce good quality oils.But the work is hard.And getting
all the oil from the seeds can be difficult.
If there is a large supply of seeds, then handoperated presses may not be enough to support a business.
Large powered presses that can operate all day are needed.
| Title |
How to 1.________Oils from Seeds |
| 2.________of oils |
People use oils when they cook meals, paint pictures and clean objects. |
| Method 1 |
●Crush the seeds between two stones and then put them into a cloth bag.
●3.________the cloth bag up.Some of the oil will flow out of the bag.
●The 4.________oil in the seeds can be got by putting more heavy rocks on them. |
| Method 2 |
●A box is used to 5.________several bags of seeds.
●Place a heavy cover on the bags.
●Use a long wooden stick to push the cover slowly.
●The 6.________of oils relies on the pressure placed on the bags. |
| Small batch presses |
●They are at a low 7.________.
●They are easy to operate and repair.
●They can be used in areas 8.________of electricity or gasoline.
●They can be operated by hand very conveniently.
●They can produce good quality oils. |
| Large 9.________ presses |
●It is easy to get all the oil from the seeds.
●They can 10.________with a large supply of seeds and support a business.
●They can run all day. |