In 2015, she graduated from college. (Complex)

• Simple Sentence এ ‘In/At the the time of/on/at/ at the very moment’ থাকলে Complex Sentence এ When বসে।
- When দিয়ে বাক্য শুরু হলে উভয় Clause কে আলাদা করার জন্য কেবল Comma বসে।

Simple: In 2020, they moved to a new city.
Complex: When it was 2020, they moved to a new city.

Simple: In 2015, she graduated from college.
Complex: When it was 2015, she graduated from college.

• Complex sentence:
- যে sentence এ একটি Principal clause এবং এক বা একাধিক Subordinate clause থাকে, তাকে Complex sentence বলে।
- Complex sentence এর subordinate clause এর শুরুতে সাধারণত if, though, although, as, because, since, so that, that, until, till, unless, when, why, who, which, where, how, before, after, whether, while বসে।