The teacher carefully criticized each student's essay, pointing out strengths and weaknesses.

criticized 是动词 criticize 的过去式。criticize 由词根 critic（批评家）和后缀 -ize（使...化）组成，意思是"指出缺点或不足"，即"批评"。在教学中，criticize 通常指建设性的批评，目的是帮助学生改进。