In the event of not doing it, you will die. (Make it Compound) -

•'Do or die': Compound sentence. - কারণ,  যখন কোনো Sentence এ একাধিক Principal 
clause যেমন, but, or, yet, therefore of Co-ordinating Conjunction দ্বারা যুক্ত হয়, তাকে Compound sentence বলে।
•There are two clauses and one conjunction. One main clause is “Do” and the other main clause is “Die”. Or is the conjunction.
অপর দিকে,
• Simple sentence এ একটি মাত্র clause থাকে। in the simple sentence, there is only one finite verb, ‘die’.