Next morning, hard on the heels of the servant bringing coffee, Mary entered their room.

第二天早上， 紧跟在端来咖啡的仆人之后， 玛丽走进了他们的房间。

It can also mean, simply, to come after something in terms of time: " The snow fell hard on the heels of the cold temperatures that began last night" .

它也可以简单地表示在时间上追求某事：“昨晚开始的低温之后，雪下得很厉害”。