what reasons are given by the author to help determine why Annemaire and Kirsti have different mannerims around the soldiers

Kirsti is younger than Annemarie and innocent in the way she sees people. Kirsti also has never known a world without the presence of soldiers..... she's never known any different, so their presence doesn't affect her in the same way it does her sister.

Annemarie is remembers the days before the Nazis moved into their city. She remembers the days when food was abundant, and the people were free to go about their business without worrying about rules and regulations. Because of this, she is far more protective and reserved.