问题
单项选择题
励磁调节器由基本控制和辅助控制两大部分组成，属于基本控制的是（）。
A.电力系统稳定器
B.励磁系统稳定器
C.综合放大单元
D.励磁限制单元
答案
参考答案：C
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励磁调节器由基本控制和辅助控制两大部分组成，属于基本控制的是（）。
A.电力系统稳定器
B.励磁系统稳定器
C.综合放大单元
D.励磁限制单元
参考答案：C
Passage 3
| Questions 11 to 15 are based on the following passage: To us it seems so natural to put up an umbrella to keep the water off when it rains. But actually the umbrella was not invented as protection against rain. It was first used as a shade against the sun. Nobody knows who first invented it, but the umbrella was used in very ancient times. Probably the first to use it were the Chinese, way back in the eleventh century B.C.. We know that the umbrella was also used in ancient Egypt and Babylon as a sunshade. And there was a strange thing connected with its use; it became a symbol of honor and authority. In the Far East in ancient times, the umbrella was allowed to be used only by royal people or by those in high office. In Europe, the Greeks were the first to use the umbrella as a sunshade. And the umbrella was in common use in ancient Greece. But it is believed that the first persons in Eu- rope to use the umbrellas as protection against the rain were the ancient Romans. During the Middle Ages, the use of the umbrella practically disappeared. Then it appeared again in Italy in the 16th century. And again it became a symbol of power and author-ity. Umbrellas have not changed much in style during all this time, though they have become much lighter in weight. (80) It wasn’t until the twentieth century that women’s um-brellas began to be made in a variety of colors. |
According to the passage, which of the following is NOT true
A．Women enjoy using umbrella with various kinds of colors
B．The inventor of the umbrella is unknown
C．Once ordinary people had no right to use umbrellas
D．Umbrellas were popular and cheap in the ancient times