If we view a science as a body of systematized knowledge, then chemistry is usually called a natural science because it (26) knowledge of the natural world. At times we may wonder (27) there is no complete system (28) all of chemistry fits perfectly. Gaps in the present system, however, show that chemistry is still a(n) (29) subject and that we (30) all of its facts, laws, and theories. (31) , chemistry as a science is very much (32) us today, and its future holds the bright promise (33) much more to come. Man’s knowledge about himself and nature has grown into (34) sciences. The growth of the separate sciences has been more developmental than intentional. The separation of the natural sciences into physical and biological sciences, and physical sciences into physics and chemistry, happily (35) a larger body of knowledge into more manageable parts. At the same time we should remember that the concepts, techniques, and applications of the various sciences are interdependent and not exclusively a part of one science or (36) . In this (37) , chemistry is a key science among the natural sciences because everyone, (38) the area of natural science he wishes to pursue, needs at least an introduction to the principles and simpler applications of chemistry as a foundation for his specialty. Chemistry deals with the (39) of matter, changes in matter, the laws and principles (40) these changes, and the concepts and theories that interpret them.
A. didn’t discovered
B. had not discovered yet
C. haven’t discovered yet
D. haven’t yet discovered
在窗体上画一个文本框、一个标签和一个命令按钮,其名称分别为Text1、Label1和Command1,然后编写如下两个事件过程: Private Sub Command1_Click() strText=InputBox("请输入") Text1. Text=strText End Sub Private Sub Text1_Change() Label1. Caption=Right(Trim(Text1. Text), 3) End Sub 程序运行后,单击命令按钮,如果在输入对话框中输入abcdef,则在标签中显示的内容是______。
A. 空
B. abcdef
C. abc
D. def