一个不存在的日期自然也就没有星期几。

A nonexistent date certainly does not have a day of the week.

youdao

起始有效日期是一个 BPEL 扩展，标准 BPEL 并没有提供它。

The valid-from date is a BPEL extension, standard BPEL does not provide it.

youdao

莫兰表示，他从来没有要求确定一个撤军日期，而是说，只要有需要，北约就应当留在阿富汗，尽管不是永远留在那里。

Morin said he never called for a withdrawal date, but rather said NATO should stay in Afghanistan as long as necessary, although not forever.

youdao