“Never, never can we thank you. I don't know what would happen to us, if it hadn’t been for Mr. Frank.” (544). Mrs. VanDaan is saying that if it wasn't for Mr. Frank, they would most likely all be dead.
“You know what your father says” (553). Mrs. VanDaan tells Anne that she has to listen to her father. Its obviously true that everyone thinks that they wouldnt be as safe as they