The pivotal battle that changed the course of the revolution took place yesterday.
Here 'yesterday' is a/an -

• The pivotal battle that changed the course of the revolution took place yesterday.
- Here 'yesterday' is an - Adverb.

• Adverb:
- Adverbs that change or qualify the meaning of a sentence by telling us when things happen are defined as adverbs of time.
- যে adverb কোনকিছু কখন/কোন সময়ে ঘটেছে তা বর্ণনা/উল্লেখ করে তাকে Adverb of time বলে।
- এই ধরনের adverb গুলো ক্রিয়া সম্পন্ন হওয়ার সময় বুঝায় অর্থা , 'when?' বা 'কখন?' উত্তর দেয়।
- এটা sentence এর শুরুতে অথবা শেষে ব্যবহৃত হয় ।

- Adverbs of time: Yesterday, today, afterwards, always, immediately, last month, now, soon, etc.