You ___________ loudly in the library.

• শূন্যস্থানে সঠিক উত্তর হবে - mustn't speak.
Complete sentence: You mustn't speak loudly in the library.

• can, could, may, might, must, ought, shall, should, will, would ইত্যাদি modal verb এর পরে verb এর পরে present form হয়।
- see, watch, feel, hear, make, bid, know, need, but, dare, let, had rather, had sooner, would better, would rather, than, except, can, could, shall, should, will, would, may, might, must এসব এর পর infinite (to) উহ্য থাকে।