Concept checking is the process of a teacher asking questions to their students to make sure they understand the vocabulary/grammar you have taught them. =)
Answer:
That
Explanation:
Who, Which, When, Whose, That, Where are 6 of your basic relative pronouns
I have hated words and I have loved them, and I hope I have made them right.” ... pg. 528
"You want to know what I truly look like? I'll help you out. Find yourself a mirror while I continue." pg. 307
"Sometimes I imagined how everything looked above those clouds, knowing without question that the sun was blond, and the endless atmosphere was a giant blue eye." pg. 350