原发性骨肿瘤的发生率为（）。

[单选题]形状复杂的零件毛坯（如壳体）应选用（）

[单选题]In every cultivated language, there are two great classes of words which, taken together, comprise the whole vocabulary. First, there are those words（1）which we become acquainted in daily conversation, which we（2）,that is to say, from the（3） of our own family and from our familiar associates, and（4） we should know and use （5 ）we could not read or write. They （6） the common things of life, and are the stock in trade of all who （7） the language. Such words may be called“popular”, since they belong to the people （8） and are not the exclusive （9） of a limited class. On the other hand, our language （10） a multitude of words which are comparatively （11） used in ordinary conversation. Their meanings are known to every educated person, but there is little （12） to use them at home or in the market-place. Our （13） acquaintance with them comes not from our mother's （14） or from the talk of our school-mates, （15） from books that we read, lectures that we （16） ,or the more （17）conversation of highly educated speakers who are discussing some particular （18） n a style appropriately elevated above the habitual（19） f everyday life. Such words are called“learned”, and the （20） between them and the“popular”words is of great importance to a right understanding of linguistic process. 请在13处填上正确答案（）

[单选题]《铁路技术管理规程》（高速铁路部分）防护网安装完毕，打开车门后，由列车长组织（）值守，直到车门关闭。

[单选题]安装在烟囱顶上的避雷针直径不应小于下列数值（）

[填空题]语言中，一个音节声调改变了，（）也随之发生变化。同样的语义，其声调的高低、轻重、缓急程度的不同能表达出不同甚至是绝然不同的含义。

[问答题]从税负活动的三个环节来理解税负归宿的概念。

[单选题]编辑工作也是一种语言文字工作，但不要求编辑人员（　　）。

[多选题]下列选项中，属于直接引起坠落的客观危险元素的情形有( )。

[单选题]下列骨折类型中，最不稳定的是（）

[单选题]男性患者，30岁。确诊哮喘入院治疗3周，经正规治疗后病情缓解，仅偶有胸闷，患者应严禁用下述哪种药物（　　）。