下列不是降滤失的物品的是()。 ["A、煤碱液","B、水解聚丙烯腈","C、Na-CMC","D、PAM"]
襟翼舵的优点是:() ①、转船力矩大;②、所需的转舵力矩小;③、所需的舵机功率小 ["①、②","②、③","①、③","①、②、③"]
当钻井液中含盐量高而pH值低时,宜用()碱比的煤碱液。 ["A、高","B、中等","C、较低","D、低"]
民族英雄郑成功于()年收复台湾 ["A、1663","B、1664","C、1665","D、1662"]
当钻井液中含盐量高而pH值高时,宜用()降滤失。 ["A、高碱比煤碱液","B、低碱比煤碱液","C、水","D、都行"]
网络经济下的竞争呈现什么样的特点?