The sentence :
It is clear that John didn't see the play.

deep structure:
[ ] pres be clear [negation that John past see the play]
do support
[ ] pres be clear [negation that John past do see the play]
negative

[ ] pres be clear [that John past do n't see the play]
extraposition

It pres be clear [that John past do n't see the play]
affix hopping

It be pres clear [that John do n't past see the play] - surface structure

Am I doing it correct?