单项选择题 GPIO模块中，每一个引脚的内部基本电路主要包括方向控制电路，输入缓冲器和 _______。 A、多路开关 B、上拉电阻 C、下拉电阻 D、输出锁存器

未知题型 Americans this year will swallow 15,000 tons of aspirin( 阿司匹林), one of safest and most effective drugs invented by man. The most popular medicines in the world today, it is an effective pain reliever. Its bad effects are relatively mild, and it is【B1】.For millions of people suffered from arthritis(关节炎) ,it is the【B2】thing that works. Aspirin, in【B3】, is truly the 20th-century wonder drug. It is also the second largest suicide drug and is the【B4】cause of poisoning among children. It has【B5】effects that, although relatively mild, are largely【B6】among users.Although aspirin was first【B7】by German company in 1899, it has been【B8】much longer than that. Hippocrates, in ancient Greece, understood the【B9】value of the leaves and tree bark which today are known to【B10】salicylates(水酸盐) ,the chemical in aspirin. During the 19th century there was a great number of experimentation in Europe【B11】this chemical, and it led in the【B12】of aspirin. By 1915, aspirin tablets were【B13】in the United States.A small【B14】of aspirin(two five-grain tablets)【B15】pain and inflammation(炎症). It also reduces down fever by【B16】with some of the body' s reactions.【B17】aspirin seems to allow down the formation of the acids【B18】in pain and the complex chemical reactions【B19】cause fever. The chemistry of these【B20】is not fully understood, and the slowing effect of aspirin is well know.【B1】A.pricyB.dearC.expensiveD.cheap

单项选择题 现代的众筹是指通过互联网和第三方支付平台完成的众筹活动，现代的众筹活动通常是利用众筹网站完成的。