ingrate

After providing him with a home for years, she felt he was an ingrate for leaving without saying thanks.

(Chinese) 在为他提供多年食宿后，他却连声谢谢都不说就离开了，她觉得他是个忘恩负义的人。

Don't be such an ingrate; you should at least acknowledge the help your mentor gave you.

(Chinese) 别这么不知好歹；你至少应该承认你的导师给过你的帮助。