在脊灰最后传播的小范围内，十分局部的地区带来的挑战，要求我们采取具有地域特点的不同工作方式。
In the final pockets of polio transmission, highly localized challenges have demanded distinct area-specific approaches.
本文综合论述灰砂砖生产中砂子颗粒级配的影响、要求和重要作用以及应当进行控制的工艺环节和措施。
The paper describes influence, importance and requirements of sand grain composition and its control methods in the sand-lime brick production.
用于强度要求不高的灰口铸铁件的焊补。
Frepair welding of grey cast iron which requires less strength.
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