变量a 中存储了一个字符,能够正确判断该字符为数字字符“0”~ “9”的VB 表达式是(  )

A．Asc(a)>=0 Or Asc(a)<=9	B．“0”<=a<=“9”
C．a<=“0”Or a>=“9”	D．a>=“0”and a<=“9”

以下流程图的运行结果是_______。

A．4 9	B．5 9
C．4 5	D．9 5

a的取值范围为(-2,0∪1,8)，在程序中可以用下列哪个表达式表示_____。

A．(a>-2-or a<="0)" or (a>="1" or-a<8)

B．(a>="-2" or a<="0)" and (a>="1" and a<="8)"

C．(a>-2-and a<="0)" or (a>="1" and-a<8)

D．(a>-2-and a<="0)" and (a>="1" and-a<8)

有如下VB程序段：
Private Sub Command1_Click()
Dim n As Integer, r As Integer, s As String
Dim t As Integer, k As Integer, v As Integer
n = 35: t = 0: k = 0
s = ""
Do While n > 0
r = n Mod 2
n = n \ 2
t = t + r
k = k + 1
s = Str(r) + s
Loop
s = Mid("0000000", 1, 7 - k) + s
v = t Mod 2
Text1.Text = s + Str(v)
End Sub
执行该程序段后，文本框Text1中显示的内容是

A．1 0 0 0 1 1 1

B．0 1 0 0 0 1 1 1

C．1 1 0 0 0 1 1

D．1 1 0 0 0 1 0 1

下列Visual Basic表达式的值等于56的是（   ）

A．Mid("1234567", 5, 2)	B．Abs(-55) + 1
C．Sqr(56)	D．Len("55") + 1