在Words中有以下代码：
Do Until Index = Len(Input)
Index永远不会递增，因此无限循环。
Vowels中也存在相同问题

下面这些对你有帮助吗？
它不是看一个句子是否包含元音，而是看元音列表是否包含句子中的每个字符。
对于单词计数，它同样会询问包含单个空格的字符串是否包含句子中的每个字符（在本例中，“单词计数”只是空格计数，因此前导或尾随空格，或者单词之间的额外空格，将被计为额外单词，就像您的代码当前所做的那样）。
它还允许我们废除单独的方法调用和手工循环代码，如您所见，这些代码容易产生小错误（我个人建议在这种情况下使用For循环而不是Do Until循环，因为For循环被设计为自动递增索引）。

Sub Main()
    Console.WriteLine("Sentence Analysis")
    Console.WriteLine()
    Console.WriteLine("Enter a sentence then press 'Enter'")
    Console.WriteLine()

    Dim sentence As String
    sentence = Console.ReadLine()

    Dim vowel_count As Integer = sentence.Count(Function(c) "aeiou".Contains(Char.ToLower(c)))
    Dim word_count As Integer = sentence.Count(Function(c) " ".Contains(Char.ToLower(c)))

    Console.WriteLine("Your sentence contains {0} words.", word_count)
    Console.WriteLine("Your sentence contains {0} vowels.", vowel_count)        

    Console.ReadLine()
End Sub

你和我上同一所大学。这是密码...

Option Compare Text
Imports System
Imports System.Diagnostics.Metrics
Imports System.Reflection
Imports System.Text.RegularExpressions

Module Program
Sub Main(args As String())
    Console.WriteLine("Sentence Analysis")
    Console.WriteLine()
    Console.WriteLine("Enter a sentence, then press 'Enter'")
    Console.WriteLine()
    Dim input As String = Console.ReadLine
    Dim letterbyletter() As Char = input.ToCharArray
    Dim counter As Integer = 1
    Dim vowelcounter As Integer
    Call wordcount(input, letterbyletter, counter)
    Console.WriteLine("Your sentence contains {0} words.", counter)
    Call vowelcount(input, letterbyletter, vowelcounter)
    Console.WriteLine("Your sentence contains {0} vowels.", vowelcounter)
End Sub
Sub wordcount(ByVal input As String, ByRef letterbyletter() As Char, ByRef 
    counter As Integer)
    For i = 0 To Len(input) - 1
        If letterbyletter(i) = " " Then
            counter += 1
        End If
    Next
End Sub
Sub vowelcount(ByVal input As String, ByRef letterbyletter() As Char, ByRef 
    vowelcounter As Integer)
    Dim vowels() As String = {"a", "e", "i", "o", "u"}
    For i = 0 To Len(input) - 1
        For j = 0 To 4
            If letterbyletter(i) = vowels(j) Then
                vowelcounter += 1
            End If
        Next
    Next
    End Sub
    End Module