第2题: [单项选择]计算机网络的传输介质中性能最好、应用前途最广泛的一种是______。 A. 无线电 B. 光纤 C. 同轴电缆 D. 双绞线 参考答案:B 答案解析:[解析] 光纤的优点体现在多个方面,首先,它的传输数据率可以达到几千Mbps,传输频带可上1014~1017Hz,因而通信容量大。其次介质传输损耗小,在无中
A. Their tasty meat. B. The principle of their defense system against disease. C. Their solid skin. D. The principle of their birth modes. 参考答案:B 答案解析:[试题分析] 本题测试的是文章的细节部分。 [详细解答] “Medical researchers want to learn more about the shark's body defen
第37题: [单项选择]Pitted reduction gear teeth having a deep blue color with evidence of overheating have been operated with () A. excessive speed B. improper warm-up C. extreme misalignment D. inadequate lubrication 参考答案:D