(+i*) S (F+*i) E (工+i*1) (E+i*i) E (E+E*1) E T (E+T (E+T*) T (E+T) F F TFE SE E + T T Fi i * F TiF ( i+i*i) ( F+i*i) ( T+i*i) (E+ i*i) (E+ F*i) (E+T* i ) (E+T*F ) (E+T ) (E) TFE S’ E ( ) S’