Code:
+--------------------------------------------------------+
  |        sex           age                     education |
  |--------------------------------------------------------|
  | Male (Sex)     25+ (Age)   Advanced (Aggregate levels) |
  | Male (Sex)     25+ (Age)   Advanced (Aggregate levels) |
  | Male (Sex)     25+ (Age)   Advanced (Aggregate levels) |
  | Male (Sex)     15+ (Age)   Advanced (Aggregate levels) |
  | Male (Sex)   15-64 (Age)   Advanced (Aggregate levels) |
  +--------------------------------------------------------+
I would like to delete everything after space . For example, in the first observation sex becomes Male; age becomes 25+; education becomes Advanced.

Code:
* Example generated by -dataex-. To install: ssc install dataex
clear
input str244 sex str11 age str31 education
"Male (Sex)"   "25+ (Age)"   "Advanced (Aggregate levels)"    
"Male (Sex)"   "25+ (Age)"   "Advanced (Aggregate levels)"    
"Male (Sex)"   "25+ (Age)"   "Advanced (Aggregate levels)"    
"Male (Sex)"   "15+ (Age)"   "Advanced (Aggregate levels)"    
"Male (Sex)"   "15-64 (Age)" "Advanced (Aggregate levels)"    
"Male (Sex)"   "25+ (Age)"   "Advanced (Aggregate levels)"    
"Male (Sex)"   "15-64 (Age)" "Advanced (Aggregate levels)"    
"Male (Sex)"   "15+ (Age)"   "Advanced (Aggregate levels)"    
"Male (Sex)"   "25+ (Age)"   "Advanced (Aggregate levels)"    
"Male (Sex)"   "25+ (Age)"   "Advanced (Aggregate levels)"    
"Male (Sex)"   "25+ (Age)"   "Intermediate (Aggregate levels)"
"Female (Sex)" "25+ (Age)"   "Advanced (Aggregate levels)"    
"Male (Sex)"   "25+ (Age)"   "Advanced (Aggregate levels)"    
"Male (Sex)"   "15+ (Age)"   "Advanced (Aggregate levels)"    
"Male (Sex)"   "15-64 (Age)" "Advanced (Aggregate levels)"    
end