When I was twenty, I started my first job.(Change into a simple sentence)

Complex: When I was twenty, I started my first job.
Simple: At the age of twenty, I started my first job.

• When যুক্ত Complex Sentence কে Simple Sentence করার নিয়ম:
- When উঠে যায় এবং when এরপরের অংশে যে Subject ও Verb থাকে টা উঠে যায়।
- ছোট সময় বুঝালে at/ in বসে।
- ঋতু বুঝালে তার পূর্বে in বসে।
- বয়স বুঝালে at the age of বসে।
- Comma (,) এরপরের অংশ বসবে।

• Other examples:
- Complex: When it is evening, the birds return to their nests.
- Simple: In the evening, the birds return to their nests.
- Complex: When it was winter, we went on a picnic.
- Simple: In winter, we went on a picnic.

Source: Advanced Learner's Communicative English Grammar & Composition By Chowdhury & Hossain.