"This is the book which I bought."

Translation: Αυτό είναι το βιβλίο που αγόρασα.

[Nevredimka]

Why Είναι το βιβλίο που αγόρασα is not correct?

[troll1995]

Because of this, which is emphatic. Emphasis in Greek is expressed by not omitting the αυτός/αυτή/αυτό. If the english sentence was It is the book which I bought, your tranlsation would be correct.

[DaithiWalsh]

But then, another sample sentence here is: 'Αυτό είναι το ρολόι το οποίο αγόρασα. This is the watch that I bought'. For me, 'the watch' is inter-changeable with 'the book' in the two sentences, so I don't see why the pronoun should be changed.

[mizinamo]

• Αυτό είναι το ρολόι το οποίο αγόρασα.
• Αυτό είναι το ρολόι που αγόρασα.

are both possible and correct.

Similarly here with

• Αυτό είναι το βιβλίο που αγόρασα.
• Αυτό είναι το βιβλίο το οποίο αγόρασα.

[Stylianos402400]

Why is it 'pou' not 'opou' here? (sorry for the transliteration, I don't have a Green keyboard)

[mizinamo]

όπου is "wherever".

που is "which, that".

[Condorandi]

mizinamo, I want to confirm that "που" is exactly the same as "το οποίο" in this sentence. I have also noticed that "Πού" means "Where" at the beginning of a question. The difference is the stress on the "υ". Αm I correct?

[troll1995]

Yes you are correct in both statements. Πού does not mean "where" only at the beginning of a question. Μου είπε πού πήγε=He told me where he went.

[Condorandi]

Great answer! Thank you so much! I guess the stress on the "υ" is very important.