You could send the array in the parent form to the child form

Parent form
Code:
Private Questions(10) As String
. . .
 Private Sub Button1_Click( _
     ByVal sender As System.Object, _
     ByVal e As System.EventArgs) Handles Button1.Click

. . .

Dim f As New frmChildForm(Questions)

Try
    f.ShowDialog()
Finally
    f.Dispose()
End Try
Child form
Code:
Public Class frmChildForm
    Private Questions() As String
    Public Sub New(ByVal sender() As String)
        InitializeComponent()
        Questions = sender
    End Sub
    Private Sub Form2_Load( _
        ByVal sender As System.Object, _
        ByVal e As System.EventArgs) Handles MyBase.Load
        ListBox1.DataSource = Questions
    End Sub
End Class
Or MainForm
Code:
Public Class frmMainForm
    Private mQuestions(10) As String
    Public ReadOnly Property Questions() As String()
        Get
            Return mQuestions
        End Get
    End Property

. . .
    Dim f As New frmChildForm

    Try
        f.ShowDialog()
    Finally
        f.Dispose()
    End Try
Child form
Code:
Public Class frmChildForm
    Private Sub Form2_Load( _
        ByVal sender As System.Object, _
        ByVal e As System.EventArgs) Handles MyBase.Load
        ListBox1.DataSource = frmMainForm.Questions
    End Sub
End Class
To add a single item
Code:
ListBox1.Items.Add(frmMainForm.Questions(0))