问题
判断题
LC自激振荡器中，我们希望每极的输入电阻大，输出电阻小。
答案
参考答案：对
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LC自激振荡器中，我们希望每极的输入电阻大，输出电阻小。
参考答案：对
| Aspirin is one of the safest and most effective drugs invented by man. The most popular medicine in the world today, it is an effective pain reliever. Its bad effects are relatively mild. It is also cheap. For millions of people suffering from arthritis, it is the only thing that works. Aspirin, in short, is truly the 20th-century wonder drug. It is also the second largest suicide drug and is the leading cause of poisoning among children. It has side effects that, although relatively mild, are largely unrecognized among users. Although aspirin was first sold by a German company in 1899, it has been around much longer than that. Hippocrates, in ancient Greece, understood the medical value of tree barks and leaves which today are known to contain a chemical found in aspirin. During the 19th century. there was a great deal of experimentation in Europe with this chemical, and it led to the introduction of aspirin. By 1915, aspirin tablets were available in the United States. A small quantity of aspirin relieves pain and inflammation. It also reduces fever by affecting some of the body’s reactions. Aspirin is very irritating to the stomach lining. The best way is to chew the tablets before swallowing them with water, but few people can stand the bitter taste. Some people suggest crashing the tablets in milk or orange juice. |
Aspirin was invented in ______.
A．the 20th century
B．the 19th century
C．ancient Greece
D．ancient Germany