There is much more potential ambiguity in natural language sentences than one might think.
Lexical Ambiguity: A word can have multiple parts of speech and multiple meanings for each part of speech.
You can verb anything. -- William Safire.The number of combinations of meanings is the product of the number of meanings for each word.
Syntactic Ambiguity: Phrases might be attached to different parts of the sentence. Especially troublesome are prepositional phrase attachment and conjunctions.
I saw the man on the hill with a telescope.
Lowering the level of the lake allows city officials to kill weeds and residents to repair their docks.