1. Amapayipi ensimbi ashiselwe okuthutha uketshezi olunomfutho ophansi (GB/T3092-1993) abizwa nangokuthi amapayipi ashiselwe ajwayelekile, aziwa kakhulu ngokuthi amapayipi amnyama.Kuyipayipi lensimbi elishiselwe ukudlulisa uketshezi olujwayelekile lomfutho ophansi njengamanzi, igesi, umoya, uwoyela nesishifu sokushisisa nezinye izinjongo.Amapayipi ensimbi...
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