well,

santa singh finishes his english test , when out side he meets banta singh. banta notices that santa is very worried.

banta : ooi yaar why are you worried?
santa: ithink i got an answer wrong yaar. i'm worried that i'll loose marks..

banta: whats the question yaar..

santa: " what is the pastense of think? "

banta : what did you answer yaar ??

santa: i dint remeber it yaar , but i thought and thought and thought and thought and thought and answered it "thunk"!, i hope its right ...