@bubu,
Quote:"It was a wonderful dinner that I had with my friends on my birthday at Holiday Restaurant".
I found this sentence in the notebook of a student. I wonder if this sentence is correct.
Yes, it is. Bubu.
Quote:Particularly the word 'that' after 'dinner' seems unnecessary. Will it be correct to say-
"It was a wonderful dinner I had with my friends on my birthday at Holiday Restaurant." [the sentence still sounds a bit stiffed up or rather 'twisted and turned'. ]
The 'that', known as the zero relative pronoun, is optional, so your example is also fine. If my memory serves me right, the zero pronoun is the most common in use in spoken English.
This happens in English, as I'm sure you know, when the relative pronoun replaces the object.
It was a wonderful dinner.
[that] I had
it/the dinner with my friends on my birthday at Holiday Restaurant.
The sentence sounds stiff because there is more than the usual amount of information being described.
Consider,
It was a wonderful dinner [that] I had with my friends on my birthday at Holiday Restaurant on the tenth of last month between the hours of 8 and 11PM after which we went to a nightclub where we danced 'til the wee hours of the morning which is why I'm really bagged today when I'm supposed to be alert for this meeting that is going to be held this afternoon.