i do not understand how the verbs in Dutch are being interchange and why there are interchange

[LeSNT2]

I'm not 100% sure if I understand your question correctly. But 'ben' in sentence 1 is not replaced bij 'hij' in sentence 2. It is replaced bij 'is' because in sentence 2 you have a main clause and a sub clause. The subject of the sub clause in sentence 2 is 'hij' so the verb 'ben' changes into 'is'.

"Peter denkt: ik ben te laat voor de les." = 2 main clauses (Peter denkt + Ik ben te laat voor de les)
"Peter denkt dat hij te laat voor de les is" = 1 main clause and 1 sub clause (Peter denkt (main clause) + dat hij te laat voor de les is (sub clause).

What happens with indirecte rede? Instead of 2 main clauses, you'll get a main clause and a sub clause. In a sub clause the finite verb (the verb that changes is the subject changes) goes to the end of the sentence. In a main clause the finite verb is at the second place.


I hope this makes things clear. If I didn't understand your question correct or if you have more questions, don't hesitate to ask!