Why the speak appears before the switching of picture.

Question

SpeechSynthesizer ss = new SpeechSynthesizer();
PromptBuilder pb = new PromptBuilder();
SpeechRecognitionEngine sre = new SpeechRecognitionEngine();
Choices clist = new Choices();
int counter = 0;
int counter_CorrectAns = 0;
public void Question()
{
string path = @"C:\Users\Tan Wei Shen\Desktop\FYP\New folder\";
string[] filePaths = Directory.GetFiles(path, "*.jpg");
pictureBox1.Image = Image.FromFile(filePaths[counter]);
ss.SpeakAsync("What is this?");
clist.Add(new string[] { "apple","chicken","eraser" });
Grammar gr = new Grammar(new GrammarBuilder(clist));
try
{
sre.RequestRecognizerUpdate();
sre.LoadGrammar(gr);
sre.SpeechRecognized += sre_SpeechRecognized;
sre.SetInputToDefaultAudioDevice();
sre.RecognizeAsync(RecognizeMode.Multiple);
}
catch (Exception ex)
{
MessageBox.Show(ex.Message, "Error");
}
}
private void WellDone()
{
timer1.Start();
sre.RecognizeAsyncStop();
label1.Visible = false;
string path = @"C:\Users\Tan Wei Shen\Desktop\FYP\correct\";
string[] filePaths = Directory.GetFiles(path, "*.png");
pictureBox1.Image = Image.FromFile(filePaths[counter_CorrectAns]);
ss.Speak("Well done");
counter++;
}
public Form1()
{
InitializeComponent();
}
private void Form1_Load(object sender, EventArgs e)
{
}
private void sre_SpeechRecognized(object sender, SpeechRecognizedEventArgs e)
{
switch (e.Result.Text.ToString())
{
case "apple":
WellDone();
break;
case "chicken":
WellDone();
break;
case "eraser":
WellDone();
break;
}
}
private void btnStart_Click(object sender, EventArgs e)
{
btnStart.Visible = false;
label1.Visible = true;
pictureBox1.Visible = true;
Question();
}
private void timer1_Tick(object sender, EventArgs e)
{
Question();
timer1.Stop();
}