Use of the pronoun 'that'

[sam.railkar]

Apologies if this is a duplicate. I have seen some conflicting uses of 'that'. When we use the pronoun 'that' in place of a noun, should the noun be singular only? Can it be plural? Response appreciated. Thanks.

[sam.railkar]

To clarify the question, look at these 2 sentences.
a) I gave Rebecca some gifts that were expensive.
b) I gave Rebecca a gift that was expensive.

1st sentence, use of that is plural.
2nd one, singular.

[mikrodj]

both of your examples are fine. You can use that with either singular or plural nouns.

You can also use that in parallel structures, such as

My car is bigger than that of my father.