问题 单项选择题

以下关于变量作用域的叙述中,正确的是 ______。

A.窗体中凡被声明为Private的变量只能在某个指定的过程中使用

B.全局变量必须在标准模块中声明

C.模块级变量只能用Private关键字声明

D.Static类型变量的作用域是它所在的窗体或模块文件

答案

参考答案:D

解析:[评析] 变量作用域分为:局部变量、窗体、模块级变量和全局变量。局部变量:指在过程内用Dim、Static语句声明的变量,只能在本过程中使用的变量。窗体/模块级变量:指在一个窗体/模块的任何过程外,即在“通用声明”段中用Dim语句或用Private语句声明的变量,可被本窗体/模块的任何过程访问。全局变量:指只能在标准模块的任何过程或函数外,即在“通用声明”段中用Public语句声明的变量,可被应用程序的任何过程或函数访问。

选择题
单项选择题

This book is written expressly for students in an attempt to present the material that is most useful and interesting to them. Previous courses in chemistry are not necessary for the understanding of the material, although those students who have had high school chemistry will find that a review of the inorganic section will better enable them to master the organic and biochemistry sections that follow.

The author has felt that in the past there was an improper selection of material from inorganic, organic, and biochemistry in the majority of the textbooks of chemistry for nurse. The tendency has been to develop the inorganic chemistry to such an extent that organic and biochemistry is covered too briefly. The recent advances in biochemistry and their widespread application to the practice of medicine and nursing have considerably altered the situation. Not only is biochemistry more closely allied to the practical chemistry of medicine and nursing but also it is of more interest to the student. In the author’s experience the response to biochemistry has always been more favorable than to the other sections. Within the brief period allotted to chemistry, therefore, the sections on inorganic, organic, and biochemistry should be so arranged that a good share of the time is spent in the study of biochemistry. This book presents mainly those fundamentals of inorganic and organic chemistry that are necessary for the understanding of the section on biochemistry.

The fundamental points suggested in the Curriculum Guide are included in the book, with some additions in the biochemistry section. The author feels that a study of urine, vitamins, nutrition, and hormones is so obviously a part of biochemistry that at least the fundamentals should be included in this course.

The book has been planned in such a way that it may be adapted to various courses in chemistry. The material suggested by the Curriculum Guide is covered in the first nineteen chapters and may be used in accelerated courses or where minimum time is allotted to chemistry. When the time allotted to the course is sixty to ninety hours, the entire contents of the book may be used to advantage. While the book has been written especially to fit the needs of Schools of Nursing, it could readily be applied in instances where students are required to take but one course in chemistry.

The apathetic attitude of nonprofessional students toward a course in inorganic chemistry may well be overcome by the proper presentation of material selected from inorganic, organic, and biochemistry.

The purpose of this book is()

A. to provide students with helpful and interesting material

B. to preface the Curriculum Guide with a brief account of biochemistry

C. to present inorganic and organic chemistry in details

D. to raise nonprofessional students’ interests in chemistry