Leaving out "That"

Noun clauses are introduced by relative pronouns. And the "king" of relative pronouns is "that".

When the noun clause comes at the beginning of the sentence (in the subject position), we must include the word "that".

However, when the noun clause is placed at the end of a sentence (in the object position), the word "that" is optional. In other words, both of the following sentences are correct:

In fact, we often leave out "that" when the meaning of a sentence is clear. Consider the following sentences, all of which are grammatically correct:

Intructions for the Quiz

Identify the underlined clause.