什么叫流量?有哪两种分类?
参考答案:流量是指单位时间内流过管道某一截面的流体数量。分为体积流量和质量流量。
To improve the quality of our products, we asked for suggestions______ had used the products.[ ]
A. no matter which
B. whichever
C. no matter who
D. whoever
为了稳定井壁,对滤失造壁性的基本要求是:(),井壁稳定。
A、滤饼好、滤失小
B、滤饼好、滤失大
C、滤饼差、滤失小
D、滤饼差、滤失大