当t=0.6，y=0时，应该执行粉红色部分，u2和v2应该不为0，可是结果为0，求指点 

program main      
      
      real  TIME,y, pi,c,H,T,u1,v1,u2,v2,ALPHA
      read(*,*)TIME,y
      pi=3.14159265
      c=1400
      H=381
      T=0.5
      IF(y.LT.31.AND.y.GE.0)THEN
      IF(TIME.LE.(T+y/c).AND.TIME.GE.y/c)THEN
      u1=sin(4*pi*(TIME-y/c))-0.5*sin(8*pi*(TIME-y/c))
      v1=4*pi*cos(4*pi*(TIME-y/c))-4*pi*cos(8*pi*(TIME-y/c))
      u2=0
      v2=0
[color=FF00FF]      else if(TIME.GE.(2H-y)/c.AND.TIME.LE.(T+(2H-y)/c))THEN
      u1=0
      v1=0
      u2=sin(4*pi*(TIME-(2H-y)/c))-0.5*sin(8*pi*(TIME-(2H-y)/c))
      v2=4*pi*cos(4*pi*(TIME-(2H-y)/c))-4*pi*cos(8*pi*(TIME-(2H-y)/c)) [/color]   
      else
      u1=0
      v1=0
      u2=0
      v2=0
      end if
      else IF(y.LT.681.AND.y.GE.31)THEN     
      IF(TIME.LT.(2H-y)/c.AND.TIME.GE.y/c)THEN
      u1=sin(4*pi*(TIME-y/c))-0.5*sin(8*pi*(TIME-y/c))
      v1=4*pi*cos(4*pi*(TIME-y/c))-4*pi*cos(8*pi*(TIME-y/c))
      u2=0
      v2=0
      ELSE IF(TIME.LE.(T+y/c).AND.TIME.GE.(2H-y)/c)THEN
      u1=sin(4*pi*(TIME-y/c))-0.5*sin(8*pi*(TIME-y/c))
      v1=4*pi*cos(4*pi*(TIME-y/c))-4*pi*cos(8*pi*(TIME-y/c))
      u2=sin(4*pi*(TIME-(2H-y)/c))-0.5*sin(8*pi*(TIME-(2H-y)/c))
      v2=4*pi*cos(4*pi*(TIME-(2H-y)/c))-4*pi*cos(8*pi*(TIME-(2H-y)/c))
      ELSE IF(TIME.GT.(T+y/c).AND.TIME.LE.(T+(2H-y)/c))THEN
      u1=0
      v1=0
      u2=sin(4*pi*(TIME-(2H-y)/c))-0.5*sin(8*pi*(TIME-(2H-y)/c))
      v2=4*pi*cos(4*pi*(TIME-(2H-y)/c))-4*pi*cos(8*pi*(TIME-(2H-y)/c))
      ELSE
      u1=0
      v1=0
      u2=0
      v2=0
      end if
      END If 
      ALPHA=19.05*(6945*(u1+u2)+7560*(v1+v2))
      write(*,*) u1,v1,u2,v2,ALPHA
      pause
      stop
      END