One should be _______ the impact their words can have on others.

• শূন্যস্থানে সঠিক উত্তর হবে - mindful of.
- Complete sentence: One should be mindful of the impact their words can have on others.

• Mindful of
English Meaning: Conscious or aware of something.
Bangla Meaning: মনোযোগী; সচেতন।
- সচেতন অর্থে mindful এর সাথে appropriate preposition হিসেবে of বসে।

Example: 
- She remained mindful of her health.
- Drivers should always be mindful of pedestrians crossing the street.
- Be mindful of your surroundings.

Source:
1. Accessible Dictionary by Bangla Academy.
2. Oxford Learner's Dictionary.