【单选题】碳素钢按碳的质量分数可分为低碳、中碳、高碳钢,中碳钢的质量分数一般是( )
【简答题】影响超声波测距的准确性有哪些因素?如何提高超声波测距仪的准确性?
【单选题】This is a _____ book that you may _____ in daily English study. [ ]
【简答题】碳的质量分数小于____的钢为低碳钢,碳的质量分数为____、的钢为中碳钢,碳的质量分数大于____的钢为高碳钢。
【简答题】When did the first daily English newspaper come out? It came out in__________.
【单选题】It's my daily duty to have the English newspapers ________ to the senior students. [ ]