She carefully affixed the stamp ____________ the envelope before dropping it into the mailbox.

• Affix (verb transitive)
- affix something (to) (আনুষ্ঠানিক) আযুক্ত/যুক্ত/সংযুক্ত করা; জুড়ে দেওয়া।
- affix a seal/stamp to a document; affix one’s signature to an agreement.

• যেমন: 
- She affixed a stamp to the envelope.
- The sticker must be affixed to your windshield.

• সুতরাং, নিয়মানুযায়ী শূন্যস্থানে to বসবে।
- Complete sentence: She carefully affixed the stamp to the envelope before dropping it into the mailbox.