1. I find that pathetic.Originally Posted by jack
"that" functions as the object of the verb, and it is modified by the adjective "pathetic". "pathetic" is an object complement. Here's the test for object complements:
1. I find that pathetic. Test => that is pathetic.
Now, if we add is to our sentence, the result is ungrammatical, 2.
2. *I find that is pathetic.
"that" has two functions: 1) as the object of "find" and 2) as the subject of is. In every sentence, each word must have only one function. "that" in 2) has more than one function.