教授在批改论文时，总是仔细地为学生的引文添加注释。

The professor spent time carefully ___annotating the students' citations while grading their papers.

研究人员正在为这些医学图像添加标签，以便机器学习算法能够更好地识别病变。

Researchers are ___annotating these medical images to help the machine learning algorithm identify abnormalities more accurately.