A:13
B:13
C:23
D:12
去年我市出现了严重旱灾,春节期间温家宝总理亲临曲阜视察灾情,并做出重要部署﹣﹣严防因干旱导致的农作物减产甚至绝收.从中可以看出( )
a(1)=False
For i = 2 To 20
a(i) = True
Next i
If a(i) = True Then
For j = 2 To 20 \ i
a(i * j) = False
Next j
End If
t = 0
For i = 1 To 20
t = t + 1
经过该程序段运行后,变量t的值为( )