What is the function of complement shown in parentheses this sentence Open that (crate) carefully.?

The word "(crate)" in the sentence "Open that (crate) carefully." is a noun phrase functioning as the direct object of the verb "open".

Here's why:

* Direct Object: The direct object is the noun or pronoun that receives the action of the verb. In this case, the crate is the thing that is being opened.

* Noun Phrase: A noun phrase is a group of words that act as a noun. "(crate)" is a single-word noun phrase.

The parentheses are used to emphasize the word "crate" as the object of the verb "open", even though it is not explicitly stated.