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问题 单项选择题

某钢结构安装工程发生整体倾覆事故，经事故调查，发现是由于设计中，验算吊装承载能力出现失误造成的。该质量事故应判定为( )。

A．社会原因引发的事故

B．经济原因引发的事故

C．技术原因引发的事故

D．管理原因引发的事故

答案

参考答案：C

单项选择题

晶体管时间续电器比气囊式时间继电器的延时范围（）。

A、因使用场合不同而不同

B、相等

C、小

D、大
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单项选择题

Imagine fishermen walking down to the seashore, ready to carry out their early morning routine of preparing their boats and net. (51) they hope for a good catch of fish. But to their (52) , a horrible sight meets their still sleepy eyes. Thousands of fish have been washed ashore dead. The cause of this mass destruction—A red tide!

Red tides are a global (53) . They have been observed on both the Atlantic and the Pacific coasts of the United States and Canada. They have also occurred in many other places. Though relatively few people are (54) them, red tides are not new.

In the Philippines, a red tide was first seen in the province of Bataan in 1908. Since then, red tides have been seen in many other (55) . A Philippines red tide expert told us that " (56) the fish kills, the Philippines has documented 1, 926 eases of dead shellfish poisoning caused by red tides. "

The term "red tide" (57) the discoloration of water that sometimes occurs in certain areas of the ocean or sea. Although the color is often red, it may also be (58) of brown or yellow. The World Book Encyclopedia reports that "the discolored areas may range from (59) a few square yards to more than 2,600 square kilometers. "

What causes such discoloration Red tides are generally caused by several species of single-celled organisms. These tiny organisms have hair-like projections which they use to (60) themselves in water.

59().

A. less than

B. more than

C. as much as

D. as little as
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