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检修设备停电，当检修设备和可能来电侧的开关、刀闸断开后，还要进一步采取什么措施？

答案

参考答案：

应断开开关和隔离开关的控制电源和合闸电源，隔离开关操作把手应锁住，确保不会误送电。

填空题

数据库系统的主要特点为数据集成性、数据的高______和低冗余性、数据独立性和数据统一管理和控制。
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单项选择题

Some spiders hunt on the ground, others build webs to trap their food, but the grass water spider catches its prey by running along the surface of the water.
This special water spider lives on the grassy banks of streams where mosquitoes, damsel flies and other insects come to feed and breed.
Although it is one of the largest spiders in New Zealand, it has an unusual ability. It doesn’t disturb the water as it waits for its meal, and there is barely a ripple when it skims across the surface at lightning speed to catch its prey.
Grass water spiders deal swiftly with larger insects like damsel flies by pulling their heads under the water and holding them there until they drown.
After a meal, the grass water spider spends up to half an hour grooming itself. It wipes its eight eyes, brushes its antennae, and takes special care to clean the hairs on its body.
It is the hairs that trap tiny bubbles of air so that the spider can run down a blade of grass and stay underwater for up to an hour when it is frightened. The hairs also keep the spider dry, even underwater.
It is only when the female spider is caring for the young that she does not hunt on the water. After mating, she produces a large egg sac, which she carries around for five weeks. Once the eggs start to hatch, she attaches the sac to some blades of grass or a thistle. She then tears the sac open and releases the tiny spiders into the nursery web.

The passage tells us that the spider ______.

A. feeds grass and thistles to its young
B. lives on blades of grass under the water
C. lives in the grass on the banks of streams
D. eats a meal once every five weeks
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