The shell bone script of the character Hook or Sentence is
The middle is character Mouth - 口 (Post 16), the two L alike are hooks. It means that the hooks hook mouth, e.g. fish mouth). 汉典（ Chinese Dictionary) says that the character Hook was same as character Sentence, which I guess that the sentence is hooked by words logically, the hook is hooked physically.
Other dictionaries don't have shell bone, bronze scripts of character Hook, they count the older scripts are just for character Sentence, not for Hook.
I agree with 汉典 (Chinese Dictionary). I think that the meaning of Hook may be a little bit earlier than that of sentence, because hook is physical characteristics, visible. Sentence is flow of thinking, logical, not directly visible. I think that shell bone script is more to be Hook meaning.
The bronze script of the character is
The big seal script of the character is