一般地，单差观测值是在（）的两个观测值之间求差。A.同卫星、同历元、异接收机 B.

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 crushing the tablets in milk or orange juice.

According to this passage, ________may NOT be the right way to take aspirin.

A．chewing the tablets

B．swallowing the tablets

C．crushing them in milk

D．putting them in dishes

一般在一个半周出现的放电脉冲幅值较大、脉冲较稀，在另一半周放电脉冲幅值较小、脉冲较密。这是哪种高频局放的放电图谱特征（）

A.电晕放电

B.内部放电

C.沿面放电

D.干扰信号

Windows 98/XP均提供了很强的多媒体功能。在下列Windows 98/XP内置的多媒体服务组件中，在字库文件的支持一下显示各种字体、字号、样式的文字主要靠哪个组件？

A．GDI

B．MCI

C．QpenGL

D．DirectX

露天粮油堆放的原则是什么？

血站对献血者每次采集血液量一般为（）

A.100ml，两次采集间隔期不少于6个月

B.100ml，两次采集间隔期不少于12个月

C.200ml，两次采集间隔期不少于6个月

D.300ml，两次采集间隔期不少于一年

E.400ml，两次采集间隔期不少于一年