and here is an example since the rustler just beat me to it
sync on : sync rate 60
backdrop on
disable escapekey : while escapekey()=0
if scancode() = 17 then result$ = " [w] key "
if scancode() = 30 then result$ = " [a] key "
if scancode() = 31 then result$ = " [s] key "
if scancode() = 32 then result$ = " [d] key "
if keystate(17)=1 and keystate(30)=1 then result$ = " [w] key and [a] key"
if keystate(17)=1 and keystate(31)=1 then result$ = " [w] key and [s] key"
if keystate(17)=1 and keystate(32)=1 then result$ = " [w] key and [d] key"
rem Etc, you can fill in the extra combinations
text 10,10,STR$(scancode())
text 10,30,result$
sync : endwhile
end