It was raining and we stayed indoors. [Complex]

Compound: It was raining and we stayed indoors.
Complex: As it was raining, we stayed indoors.

• Compound to complex: And যুক্ত Compound কে Complex করার নিয়ম:
- Sentence এর প্রথমে since/as/when বসে,
- প্রথম Sentence বসে,
- and এর পরিবর্তে comma(,) বসে,
- দ্বিতীয় sentence বসে।
Structure: Since/As/When + প্রথম Sentence + and এর পরিবর্তে comma(,) + দ্বিতীয় sentence.

• সুতরাং, নিয়মানুযায়ী,
• Compound: She was tired and could not complete the assignment.
• Complex: As she was tired, she could not complete the assignment.

Source: Advanced Learner’s by Chowdhury & Hossain