SOX is an alternative（1）for XML.It is useful for reading and creating XML content in a（2）.editor.It is then easily transformed into proper XML.SOX was created because developers can spend a great deal oftime with raw XML.For many ofus,thepopular XML（3）have not reached a point where their tree views,tables and forms can completely substitute for the underlying（4）languagE.This is not surprising when one considers that developers still use a text view,albeit enhanced,for editing other languages such as Java）SOX uses（5）to represent the structure of an XML document,which eliminates the need for closing tags and a number of quoting devices.The result is surprisingly clear.
空白（4）处应选择（）
A.programming
B.command
C.markup
D.interactive