Hi! I used

Highlight duplicate question in MS Word Document in C# Windows Forms

 it’s worked.

But I have problem when I input any sign in duplicate sentence program can’t define duplicate. I want delete all sign from sentence before define.

@1. The capital of Afghanistan.

$A) Kabul; $B) Delhi; $C)Dushanbe; $D)Tokyo.

@2. The capital of India.

$A) Kabul; $B) Delhi; $C)Dushanbe; $D)Tokyo.

@3. The capital of Tajikistan.

$A) Kabul; $B) Delhi; $C)Dushanbe; $D)Tokyo.

@4. -The capital of Tajikistan.

$A) Kabul; $B) Delhi; $C)Dushanbe; $D)Tokyo.

@5. The capital, of India.

$A) Kabul; $B) Delhi; $C)Dushanbe; $D)Tokyo.

@6. The capital of Afghanistan!.

$A) Kabul; $B) Delhi; $C)Dushanbe; $D)Tokyo.

Here all question duplicate but program can’t define because have difference sign. I want delete all sign (,/-!:;?). only for me need one sign in end sentence. In end sentence may put . or : or ! or ?.  In end sentence can’t put -. Or .? or :!.

How I can delete all sign beside one sign end sentence?