关于TCP／IP参考模型的描述中，正确的是
D.互联层的核心协议是IP协议

问答题216

单项选择题古生物学与地质学发现，一些新物种出现的突然性和缺少中间过度类型的现象，达尔文对此的解释是：新种在短时间内快速形成。 A、正确 B、错误

未分类题The attitude of those who are 'barking up the wrong tree' towards the primacy of US in the 21st century seems to be ______.A.indifferent.B.optimistiC.C.indignant.D.apprehensivE.

不定项选择‍20世纪现实主义文学深受现代主义潮流的影响，吸纳了大量现代主义的艺术技巧和写作手法。‍<b

未分类题When mentioning 'the something-for-nothing days'(Paragraph 2), the writer is talking about ______.A.Mr. Blair's unique commitment to public-service reforms.B.blank cheques given as a compromise to health workers.C.Mr. Blair's pledge to spending increases on public services.D.pay and conditions granted to health-service workers.