What is the simple subject of sentence Half result a good intention are evil?

The simple subject of the sentence "Half the results of a good intention are evil" is results.

Here's why:

* Subject: The subject of a sentence is the person, place, thing, or idea that the sentence is about.

* Simple Subject: The simple subject is the main word or group of words within the subject that performs the action of the verb.

In this case, the sentence is about the "results" of a good intention, and "results" is the main word performing the action of "are."