我正在值班，要值到明早8点钟。

I'm on now till 8 tomorrow morning.

《牛津词典》

我八点钟就到医院了，但是九点钟我才去值班。

I arrive at the hospital at eight o 'clock, but I don't go on duty until nine.

youdao

营长对值班军官说：“明晚大约八点钟，哈雷彗星将可能在这个地区看到，这颗彗星每隔76年才能看见一次。”

Battalion commander of the duty officer said: "tomorrow evening about eight o 'clock, Halley's comet will be in the area to see the comet can be seen once every 76 years."

youdao