He is engaged in teaching.

They engage in regular exercise.

他们从事于固定运动.

The professor has employed himself in researching ancient Chinese history.

教授从事于古中国历史的研究.

It was here that the doctor engaged in a study of snakes.

正是在这儿,博士从事于蛇类的研究.

I have been working on a number of potentially lucrative business deals.

我一直从事于一些具潜力而有利可图的买卖.

We specialize in research and development of plastic puffing machines.

长期从事于吹膜机的开发、设计、试制和生产.

He is currently engaged in dialect research.

他目前从事于方言的研究.

I am afraid I can not be certain about that.

恐怕此事我不能肯定.

Could you check again to be certain it is missing?

您再检查一遍,确定是否遗失了,好 吗 ?

Would it be possible to see a list of your patients, just to be certain?

再确定一下, 别人能看到你们病人的名单 吗 ?

You may be certain he never went back to school.

你可以肯定,他决不会回学校.

We can only guess ( ie We cannot be certain about ) what happened.

我们只能猜测发生了什麽事.

Be certain you catch your train on time.

务必准时赶上火车.

Accept full responsibility for one's error.

对自己的的错误负完全责任.

We need to build better cars for less money.

我们需要用较少的的钱制造出更好的汽车.

We don't know that their design was so bloody.

我们不知道他们有这种凶残的的打算.

In the second part, it main discussion in Xiang army foundation period, the aides and staff have an effect on found Xiang army, in the aspects of army and naval together with raises funds.

第二部分主要探讨在湘军创建期间，幕僚对湘军陆师、水师创建及筹饷的影响。

To protect against such enemies gaining too much power, he has handpicked former aides and staff officers to serve in key positions, and will only hand power over to his most trusted allies.

为了防止这样的敌人获得过多的权力，丹瑞精心挑选助手和参谋人员担任关键职位，仅仅将权力移交给他最信任的盟友。

Warlord's aides and staff politics is a kind of non-institutionalized politics.

军阀幕僚政治属于一种非制度化政治参与。

Meanwhile, the negative influence of the aides and staff not only led to his ultimate military failure, but also made it more tor ˉ tuous for him to progress in politics and transform in thinking.

同时其消极影响成为导致冯玉祥在军事上最终失败的重要原因，使冯玉祥在政治上进步和思想上的转变更加曲折。

As you can see, we're still working.

如你所见，我们仍在工作。