Americans this year will swallow 15,000 tons of aspirin, one of S1.______ safest and most effective drugs invented by man. As the most popular medicines in the world today, it is an effective pain reliever. Its bad S2.______ effects are relatively mild, and it is cheap. For millions of people suffered from diseases, it is the only thing S3.______ 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, ff relatively mild, S4.______ are largely unrecognized between users. S5.______ Although aspirin was first sold by German company in 1899, it has been around much longer than that. Hippocrates, in ancient Greece, understood the medical value of the leaves and tree bark which today is known to contain salicylates(水杨酸盐), the chemical S6.______ in aspirin. During the 19th century, there was a great number of S7.______ experimentation in Europe with this chemical, and it led in the introduction of aspirin. By 1915, aspirin tablets were available in the S8.______ United States. A small quantity of aspirin (two five-grain tablets) relieves pain and inflammation. It also reduces down fever by interfering with some S9.______ of the body's reactions. Specifically, aspirin seems to slow down the formation of the acids involved in pain and the complex chemical reactions that cause fever. The chemistry of these acids is not fully understood, and the slow effect of aspirin is well known. S10.______ 【S1】