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 vital great importance of specialized teaching, but additionally asserts which the study on the humanities (人文学科)and social sciences will have to stay central p... https://medium.com/@PropertyforSaleingurgaon