This could have worked if I — been more cautious.

✅ কেন সঠিক: Third conditional: could have + V3 থাকলে if-clause-এ had + V3 — If I had been more cautious।

❌ অন্য অপশন: have, might বা would বসালে গঠন ভুল হয়।

💡 মনে রাখুন: If + had + V3, … would/could have + V3।

📖 শব্দার্থ: cautious = সতর্ক