Specimen可与sample换用，但常指人或物中选出的有代表性部分，或指供科研、化验或检验用的标本。 主要内容如下:分 析介绍了几种常见抽油泵的工作原理、构造 、 适用范围及分类. The most up-to-date congressional report acknowledges the essential importance of complex coaching, and also asserts that the research with the humanities (人文学科)and social sciences must continue to be central parts of ... https://justpaste.it/8a1j2