They saved money so that they could buy a house. (Simple)

• So that যুক্ত complex কে simple করার নিয়ম:

- প্রদত্ত sentence এর প্রথম থেকে so এর পূর্ব পর্যন্ত বসে,
- so that থেকে many/might/can/could/ পর্যন্ত উঠে যায়,
- to বসে,
- প্রদত্ত sentence এর বাকি অংশ বসে।

Complex: He worked hard so that he could thrive.
Simple: He worked hard to thrive.

Complex: They saved money so that they could buy a house.
Simple: They saved money to buy a house.

Source: Advanced Learners by Chowdhury & Hossain.