求VB高手看下我哪里有问题....

Option Explicit
Dim p, w, s, f, d

Private Sub Command1_Click()
p = Val(Text1.Text)
w = Val(Text2.Text)
s = Val(Text3.Text)
If s < 250 Then
d = 0
f = p * w * s * (1 - d)
ElseIf 250 <= s And s < 500 Then '改一下
d = 0.02
f = p * w * s * (1 - d)
ElseIf 500 <= s And s < 1000 Then '改一下
d = 0.05
f = p * w * s * (1 - d)
ElseIf 1000 <= s And s < 2000 Then '改一下
d = 0.08
f = p * w * s * (1 - d)
ElseIf 2000 <= s And s < 3000 Then '改一下
d = 0.1
f = p * w * s * (1 - d)
ElseIf s >= 3000 Then
d = 0.15
f = p * w * s * (1 - d)
End If
Text4.Text = f
End Sub

250<=s<500 不能这样写！
写成 s>=250 or s<500