She was a placid child who rarely cried.她是个安静的孩子, 很少哭闹。

He had been leading a placid life for the past eight years.他8年来一直过着平静的生活。

the placid waters of Lake Erie伊利湖平静的湖水

Marcus remained placid in the face of her outburst.马库斯面对她的发飙保持平静。