A:It's time to get up.
B:It's time to have lunch.
某中学八年级一班的小张同学不幸得了白血病,班里的同学发扬了互助友爱精神,纷纷把自己平时积攒下来的零用钱捐献给小张同学治病。该班同学的行为是( )