Speak softly lest you ________________ the sleeping baby.

Lest এর ব্যবহার:
→ Lest একটি conjunction & এর অর্থ হল 'পাছে/যাতে না'। 
→ মূলত এটি negative অর্থে বাক্যে ব্যবহৃত হয়ে থাকে।

Structure: Independent clause + lest যুক্ত Dependent clause.
অর্থাৎ, subject + verb + other words + lest + subject + (should/might) + base form of verb + other words.

Complete Sentence: Speak softly lest you should disturb the sleeping baby.

Example Sentence:
1. Asif double-checked the presentation slides lest he should make a mistake during the meeting.
2. Jerin ran fast lest she should miss the class.
3. Jamil studied diligently lest he should fail the exam.
 
Source: Advanced Learner’s Grammar & Composition by Chowdhury & Hossain.