Keystones
n. 重点( keystone的复数形式 ); 要旨; 基本原理; 拱心石
🗣️ 情景例句
Charley was the star of the team.
Charley，是当时队里的明星。
She failed to call the office to cancel her appointment.
她没能打电话给办公室取消她的约会。
They will be arriving here tomorrow.
明天就要到达此地。