全国性的

Dust the baseboards? Are you kidding? Ironically, though, American women seem quite satisfied with their housekeeping, according to a national survey conducted in 1995-96. Besides that, people are designing their homes with low-maintenance features--tile in bathrooms and kitchens as well as marble on countertops--to cut down on the need for frequent cleaning. Even so, more and more people are hiring outside help to clean their houses. A Roper poll found that one in six Americans hired cleaning help last year, up from one in 10 in 1986. One professional housecleaning service, Merry Maids, has grown to over 800 franchises in recent years.

但可笑的根据一九九五／六年做的一项全国性调查美国妇女似乎对他们的家务整理挺满意除此之外人们以较不需要时时清洁的材料来设计他们的家--在浴室及厨房贴磁砖以及做大理石的台面--减少打扫的次数即使如此越来越多的人雇用外人协助清理屋子一项洛普民意调查发现去年有六分之一的美国雇用清洁服务较一九八六年的十分之一比率上升许多一个专业性的家务清理服务「快乐女佣公司」在最近几年已成长到有八百多家的连锁店

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。