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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.
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举一反三
【多选题】下列关于克雷格·温特尔说法正确的是()。
A.
他测序出了人类基因组
B.
他合成了生命
C.
他合成的人工支原体没有借用天然的支原体外壳
D.
他参加过越战
【简答题】81的平方根是__________
【单选题】请问项梁、项羽叔侄二人诛杀郡守开始反秦起义的地方是
A.
彭城
B.
会稽
C.
定陶
D.
东阳
【判断题】女子篮球是1976年第二十一届奥运会被列为奥运会正式比赛项目。
A.
正确
B.
错误
【简答题】225的平方根是_______,0.81的算术平方根是_______, 的平方根是_______,
【单选题】在下列说法中:①0.09是0.81的平方根;②-9的平方根是±3;③(-5) 2 的算术平方根是-5;④ -2 是一个负数;⑤0的相反数和倒数都是0;⑥ 16 的平方根是±4;⑦已知a是实数,则 a 2 =|a|;⑧全体实数和数轴上的点一一对应.正确的个数是(  )
A.
1
B.
2
C.
3
D.
4
【单选题】下面哪类气溶胶不是冰核的主要来源()。
A.
沙尘气溶胶
B.
黑碳气溶胶
C.
花粉工业生产
D.
可溶性硫酸盐
【单选题】在下列五个说法中,正确的有(  )个 ①0.9是0.81的平方根;②0的相反数和倒数都是0;③ 3 -5 是一个负数; ④已知a是实数,则 a 2 =|a| ;⑤全体实数和数轴上的点是一一对应.
A.
1
B.
2
C.
3
D.
4
【简答题】在下列说法中①0.09是0.81的平方根;②-9的平方根是±3;③ 的算术平方根是-5;④ 是一个负数;⑤0的相反数和倒数都是0;⑥ ;⑦已知a是实数,则 ;⑧全体实数和数轴上的点一一对应,正确的个数是(    )。
【简答题】∵ ,∴0.81的平方根是_______,算数平方根是_______。
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