He worked very hard so that he could succeed in life. (Compound).

• So that যুক্ত complex sentence কে compound করার নিয়ম-
- Subject + wanted + to + মূল verb + --- + and//and so + subject + could উঠে গিয়ে মূল verb এর past form হবে।
Example:
Complex: He worked very hard so that he could succeed in life.
Compound: He wanted to succeed in life and so he worked very hard.