I don’t understandwhat he is trying to say. The underlined part is -

• I don’t understand what he is trying to say. The underlined part is - Noun clause.
- প্রদত্ত বাক্যে 'what he is trying to say' clause টি Transitive Verb এর Object হিসেবে Noun clause হয়েছে।

• A noun clause is a group of words that band together and act like a noun.
- Nouns clauses are used when a single word isn't enough.
- They're always dependent clauses.

• একটি বাক্যের চারটি স্থানে Noun clause  বসতে পারে -
1. Subject হিসাবে,
যেমন: What will he do is uncertain.

2. Transitive verb এর object হিসেবে,
যেমন: I believe what you have said.

3. Linking verb এরপরে complement হিসাবে,
যেমন: The reason is why they are angry.

4. Preposition এরপরে,
যেমন: Listen to what they say.