可燃物不经点火,由______而引起的自发燃烧叫______,为避免这一现象,要

题型:填空题

问题:

可燃物不经点火,由______而引起的自发燃烧叫______,为避免这一现象,要注意不可将可燃物堆放得而______,并要注意通风或经常______,以降低温度.

考点:爆炸、自燃
题型:填空题

动物细胞培养主要用于生产疫苗、激素、()、多肽因子、酶等

题型:填空题

我国东北平原的土壤以及主要农作物是(   )

A.黄土,水稻、小麦、大豆

B.红土,水稻、油菜、甘蔗

C.水稻土,水稻、甜菜、大豆

D.黑土,春小麦、玉米、大豆

题型:填空题

Domestic (驯养的) horses now pull ploughs, race in the Kentucky Derby, and carry police. But early horses weren’t tame (驯服的) enough to perform these kinds of tasks. Scientists think the first interactions humans had with horses were far different from those today.

Thousands of years ago, people killed the wild horses that lived around them for food. Over time, people began to catch the animals and raise them. This was the first step in domestication.

As people began to tame and ride horses, they chose to keep those animals that had more desirable characteristics. For example, people may have chosen to keep horses that had a gentle personality so they could be ridden more easily. People who used horses to pull heavy loads would have chosen to keep stronger animals. Characteristics like strength are partly controlled by the animals’ genes. So as the domesticated horses reproduced, they passed the characteristics on to their young. Each new generation of houses would show more of these chosen characteristics.

Modern day horse breeds come in a wide variety of shapes and sizes. This variety didn’t exist in the horse population before domestication. The Shetland horse is one of the smallest breeds—typically reaching only one meter tall. With short, strong legs, the animals were bred to pull coal out of mine shafts (矿井) with low ceilings. Huge horses like the Clydesdale came on the scene around 1700. People bred these heavy, tall horses to pull large vehicles used for carrying heavy loads.

The domestication of horses has had great effects on societies. For example, horse were important tools in the advancement of modern agriculture. Using them to pull ploughs and carry heavy loads allowed people to farm more efficiently. Before they were able to ride horses, humans had to cross land on foot. Riding horses allowed people to travel far greater distance in much less time. That encouraged populations living in different areas to interact with one another. The new from of rapid transportation helped cultures spread around the world.

1. Before domestication horses were ______.

A. caught for sports

B. hunted for food

C. made to pull ploughs

D. used to carry people

2. The author uses the Shetland horse as an example to show ______.

A. it is smaller than the Clydesdale horse

B. horse used to have gentle personalities

C. some horses have better shaped than others

D. horses were of less variety before domestication

3. Horses contributed to the spread of culture by ______.

A. carrying heavy loads

B. changing farming methods

C. serving as a means of transport

D. advancing agriculture in different areas

4. The passage is mainly about _______.

A. why humans domesticated horses

B. how humans and horses needed each other

C. why horses came in different shapes and sizes

D. how human societies and horses influenced each other

题型:填空题

被审计单位资本公积以下途中合法的是()。

A.发放现金股利

B.用于职工福利

C.转增资本

D.购置低值易耗品

题型:填空题

如图所示:原图形是一个绿色填充的闭合路径,图形带有一个投影效果(见图A),执行Object>Path>Split Into Grid(对象>路径>划分为网格),划分行数和列数均设置为2,其他保留默认值。执行后结果是以下哪一个()。

A、A(无变化)

B、B

C、C

D、D

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