因为工作的缘故,我回来的时候真是太累了.
这里是“疲劳,疲倦”的意思；与...密切联系;忙於
1. 系住
He tied up the horse and went into the inn.
他系住马,走进了小酒店.
2. 使受阻
The traffic had been tied up for three hours.
交通阻塞已有三个小时.