This is the 10204th most frequent Russian word.
благодарил
"Благодарил" means "thanked" in English.
Here, "благодарил" is used to describe an act of expressing gratitude from one person to others for their assistance.
Он всерьез благодарил своих друзей за поддержку.
He sincerely thanked his friends for their support.
In this sentence, "благодарила" indicates Maria's action of showing gratitude in a formal setting.
Мария благодарила преподавателей на торжественном собрании.
Maria thanked the teachers at the formal gathering.
Here, "благодарили" is in plural form, as it represents a group showing gratitude to another person, Mrs. Sokol.