To cultiva te and impro ve students ' ability in opera tio nal thinking and application, the autho r
present a “ 3+ 2” model in teaching refo rm. The mo del include th ree teaching me tho ds—— case, inte rest and
helpma te o f com puter , tw o co ntro l methods— — leav e homew o rk and check ov er it. The pape r t ries to o ffer
some elicita tio n to the cour se refo rm.
