Can that be omitted here?

Yes, grammatically fine, it's better to remove it.

Hello, object clause (that ellipsised).

Note: In the object clause, that can be omitted in general, but that can not be omitted in any case when guiding the object clause. That cannot be omitted in the following cases:

and concatenate two object clauses, and that cannot be omitted when the that object clause is placed after and.

When the object clause guided by that is used as the object of the preposition, that cannot be omitted.

Cases where only that can be used as a relative pronoun in a definite clause a) In the there be sentence structure, only that is is used instead of which. b) When indefinite pronouns, such as anything, nothing, the one, all, much, few, any, little, etc., are used as antecedents, only that, not which.

c) When the antecedent is modified by the only, the very, only that is used. d) When the antecedent is the highest order of ordinal numerals, numerals, and adjectives, only that should be usede) When the antecedent is both a person and a thing.

That in the definite clause cannot be omitted when acting as a subject in the definite clause, but it can be omitted when it is an object. For example: this is the book (that) (referring to the previous book) i bought yesterday

I like the book that (ditto) is intrersting

Hello, these rocks contain ancient water that has been trapped inside them for million of yearsThe that in this sentence cannot be omitted, because that acts as Huaixun (subject) in the definite explicit clause, so it cannot be omitted and substituted for ancient water.

ancient waterfor million of years.

They refers to the subject of these rocks relative pronoun that modifies the object of ancient water, which acts as the subject of the clause in the clause. It can only be omitted if that acts as an object in a clause.

Hello, it can be omitted in this sentence. And be cautious, you can also omit all the content behind that. Search for the cooktop sentence as follows: it is a pity

Hello, you can omit it in this sentence. In addition, you can omit everything on the side of the pants after Hu Luxiang, such as the following sentence: it is a pit

Hello, you can omit it in this sentence, or you can omit everything that follows it, as follows: it's a pit.

Hi, you can omit it in that sentence. Moreover, you can also omit everything that follows, such as the following sentence: This is a pit.