People say that industry is the key to success. (Make it passive)

• Active voice এ people + stative verb (know, think, understand, know, find, say, etc) + that + clause থাকলে, passive করার নিয়ম হচ্ছে - 
- It is /was (tense অনুযায়ী) + প্রদত্ত verb এর past participle form + that + clause টি।

সুতরাং, নিয়মানুযায়ী, 
• Active: People say that industry is the key to success.
•Passive: It is said that industry is the key to success.