coaster释义：
n. 沿岸贸易船杯托，小托盘雪橇
例句：
Sophie will ask you to put your glass on a coaster.
苏菲会让你把杯子放在杯垫上。
Would you mind using a coaster to protect the surface of the table?
你介不介意用杯垫保护一下桌面
词组：
roller coaster过山车云霄飞车情绪急转突变
