Is this a homework question?
Student or Learner
Regarding the sentence :-I have found the pen .............. I had lsot
what will be the right answer?
3:-both can be right (if so please explain)
I have found it in a book written as :-This is the pen which I had lost but according to my knowledge, here that will make more sense so I used it in a format so as the appeal of the question is increased.
I am just trying to improve my Grammar and I am not in a school so there will not be any chance that I need help for homework :)
Fair enough. Your sentence structure involves a relative clause. In nonrestrictive (non-defining) relative clauses, we do not not use 'that", we can use "which". In restrictive (defining) relative clauses, we can use either. Your clause is defining (it defines a particular pen). Therefore, either pronoun will work.
***** NOT A TEACHER *****
Hello, Sahil Dhankhar:
I believe that most American teachers suggest "that" for a defining clause (when the information is absolutely necessary for identification).
I have read that in some varieties of English, "which" is also perfectly fine for defining clauses.
And, as one moderator reminded me recently, in such a sentence as yours, the so-called zero relative pronoun is possible and even probable in speech:
"I have found the pen I had lost yesterday."
As you said, "both can be right."
BUT if you are being tested by an American teacher, I suggest that you use "that."
P.S. In my opinion, maybe many native speakers would find the past tense more natural than the past perfect in that sentence: "I have found the pen (that) I lost yesterday."