I think timer() is your best bet.
t=timer()
while t+0.5>timer():wend
Ahhh, that takes me back.
Alternately,
do
...
time#=timer()-t#
distance = speed x time# (etc.)
t#=timer()
time2#=timer()-s#
if time2#>=0.25
print "k"
s#=timer()
endif
...
loop
Just some examples, on calculating the time passed in a frame, and also calling events every specific time interval, although you will have to check the units of timer(), 0.25 might mean 0.25s or 0.00025s, I can never remember.
Once I was but the learner,
now, I am the Master.