对电力系统的稳定性干扰最严重的故障一般是( )。 A.投切大型空载变压器; B.

题型:单项选择题

问题:

对电力系统的稳定性干扰最严重的故障一般是( )。

A.投切大型空载变压器;
B.发生三相短路故障;
C.发生两相接地短路;
D.发生单相接地。

考点:注册电气工程师发输变电专业电气主接线
题型:单项选择题

Most sharks are dangerous. The largest kind of sharks—the whale shark—has small teeth and is quite harmless to people. However, blue sharks, tiger sharks, white sharks and hammerheads are enemies of man.

Man-eaters are always a danger to swimmers in shark waters. Sometimes, though, men have used strange methods when they’re suddenly faced with a shark.

During world War Ⅱ, soldiers and sailors whose boats or planes were destroyed drifted(漂流) helplessly on the ocean in small rafts(筏子). While waiting to be saved, the men had to struggle to stay alive and were often attacked by sharks. In some cases, they had few weapons to protect themselves with. They found that just splashing(溅水) water seemed to help keep the sharks away.

One sailor was swimming for his life in the Atlantic Ocean after his boat had been blown up. He saw a shark swimming towards him. He hit the shark with his bare fist, and that drove it off.

Once, in Australia, a fisherman was fishing after sunset. He hooked a big fish and drew it towards the shore. His line broke when the fish was only a few yards from the shore. The fisherman waded(涉水) into the water to try to catch it with his hands. In the dim light, it looked like the kind of fish that could be dealt with without danger.

He put his arms around the fish and wrestled with it. Dragging it to the beach turned out to be harder than he had expected, but at last he pulled it in. When he turned a light on it, he was amazed. He had caught a shark. It was small for a shark, but it was the man-eating type and was about as long as a tall man.In a word, the best way to deal with sharks is to keep far away from them.

60. The shark that is least dangerous to man is the ________.

A. white shark      B. whale shark   C. tiger shark     D. hammerhead shark

61. This story tells you that sharks are usually ________.

A. friendly         B. small         C. afraid of people     D. dangerous

62. After the Australian fisherman found he had caught a shark, he was _________.

A. surprised      B. frightened      C. unhappy      D. angry

63. This story tells you that the best way to handle sharks is to ________.

A. hit them with your fist                 B. keep far away from them

C. splash water                         D. wrestle with them

64. The passage mainly tells us something  ________.

A. about fishing sharks                  B. about sharks

C. how to eat  sharks                   D. that sharks are man’s enemies

题型:单项选择题

根据有关规定,检验检疫机构对法定检验以外的进出口商品实施抽查检验

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治滑脱诸证宜用()

A.牡蛎

B.朱砂

C.磁石

D.龙骨

E.琥珀

题型:单项选择题

血小板彼此黏着的现象称为血小板()。

A.黏附

B.聚集

C.释放

D.凝集

题型:单项选择题

利用平板、弯管等来改变流过管路的流体流动方向,检测出动量而求出流量的是()的测量方法。

A、容积测量原理

B、流速测量原理

C、动量原理

D、差压原理

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