问题 问答题 简答题

金属容器内使用电气工具的要求?

答案

参考答案:

1、在金属容器(如汽鼓、凝汽器、槽箱等)内工作时,必须使用24V以下的电气工具,否则需使用Ⅱ类(结构符号——)工具,装设额定动作电流不大于15mA、动作时间不大于0.1s的漏电保护器,且应设专人在外不间断地监护。

2、漏电保护器、电源联接器和控制箱等应放在容器外面。

阅读理解

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     Sharks are among the oldest animals on Earth.There are hundreds of kinds of sharks.Most are about

two meters long.The dogfish shark, however, is less than twenty centimeters in length.A shark has an

extremely good sense of smell.It can find small amounts of substances in water, such as blood, body

liquids and chemicals produced by animals.__1__ Sharks eat fish, other sharks, and plants that live in the

ocean.

     Sharks grow slowly.About forty percent of all sharks lay eggs.__2__Some sharks carry their young

inside their bodies as humans do.Some sharks are not able to reproduce until they are twenty years old.

Most reproduce only every two years.And they give birth to fewer than ten young sharks.For this reason, overfishing of sharks is of special danger to the future of the animal.

     Sharks are important for the world's oceans.They eat injured and diseased fish.Their hunting activities

mean that the numbers of other fish in ocean waters do not become too great.__3__

People hunt sharks for sport, food, medicine and their skin.Experts say the international market for some

kinds of sharks has increased because many parts of a shark are valuable.

     Collectors pay thousands of dollars for the jaws of a shark.__4__The skin of a shark can be used like

leather.

     In Asia, people enjoy a kind of soup made from shark fins.Experts say a fisherman can earn a lot of

money for even one kilogram of shark fins.Sharks are among the oldest animals on Earth, but some sharks are in danger of disappearing from Earth.__5__

A. Shark liver oil is a popular source of Vitamin A.

B. This protects the plants and other forms of life that exist in the oceans.

C. Sharks are valuable to us and we can make full use of them.

D. These powerful senses help sharks find their food.

E. If too many sharks in one area are killed, that group of sharks may never return to normal population

    levels.

F. They are a threat to other forms of life in the ocean.

G. The others give birth to live young.

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