The Sentence Diagram Generator will visually represent the grammatical structure of the sentence: "Looking carefully over his test before he gave it to the teacher, Grant found several questions that he had not answered."

1. Main Clause: "Grant found several questions"

   • Subject: Grant
   • Verb: found
   • Direct Object: several questions

2. Participial Phrase: "Looking carefully over his test before he gave it to the teacher"

   • Participle: Looking
   • Adverb: carefully
   • Prepositional Phrase: over his test
     • Preposition: over
     • Object of the Preposition: his test
   • Subordinate Clause: "before he gave it to the teacher"
     • Subject: he
     • Verb: gave
     • Direct Object: it
     • Prepositional Phrase: to the teacher
       • Preposition: to
       • Object of the Preposition: the teacher

3. Relative Clause: "that he had not answered"

   • Relative Pronoun: that
   • Subject: he
   • Verb: had answered
   • Negation: not

This structure can be visually diagrammed using the Sentence Diagram Generator to illustrate the relationships between the components of the sentence.