I can't be on duty tonight, would you please take my place?

I'd love to come. But I have to be on duty this weekend night.

我是想过来, 但我周末晚上得值班.

Experienced banquet waiters must also be on duty.

还必须让有经验的宴会服务员当班.

The mountains appear to be on fire as they peer up at the drifting clouds.

云过之处群山红似火,而夏季的炎热更是火气冲天.

Doctor my whole body seems to be on fire , I don't know what to do.

医生,我整个身体都火辣辣的, 该怎么办啊!

Oh, then your barn must be on fire.

哦, 那么,也许是你家的牛棚着火了.

When I held up my hand , it , too, seemed be on fire.

我抬起手来时, 手似乎也着火了.

But at the theater my brain still seemed to be on fire.

但是晚上到了剧院之后,我的脑子还是像火烧一样.

Look at that smoke, That building must be on fire.

看那些烟, 那幢大楼一定是失火了.

Her head appears to be on fire but that is only a trick of the light.

她的头部看上去像是着火了，但那只是灯光造成的幻觉。

As far as possible , without surrender, be on good terms with all persons.

不放弃, 同所有人保持良好的关系.

You have to be on good terms with its frequenters.

你还得和常客有交情.

You be on guard against bad company.

你应该提防交错朋友.

We thought it best to be on guard.

我们觉得最好还是保持警锡.

Be on guard. There are pickpockets around here.

要提高警惕, 这里有扒手.

We must be on guard against hidden enemies.

我们必须警惕暗藏的敌人.

Be on guard when somebody flatters you.

有人奉承你时,一定要当心.

We should be on guard against obsequiousness under the name of popularization.

我们必须警惕在平民化名义下的媚俗化趋势.

We should be on guard against the enemy's invasion.

我们要防范敌人的入侵.

Emotions will hit like lightning today, so be on guard for surprises.

今天,你也许会被情绪闪电般的击倒, 所以,请小心意外.

He told us again and again to be on guard.

他一再要我们提防.