Discretional
a. 自由决定的, 任意的
✅ 同义词
🗣️ 情景例句
She is giving me piano lessons in exchange for her English classes.
我教她英语，她教我弹钢琴。
Know something like the palm of one's hand.
熟知其事，了如指掌。
Elephants like to have one master just as dogs do,
大象和狗一样，喜欢有一个专一的主人，