to think that something is true, although you do not have definite proof

假定，假设，认为;

I didn't see your car, so I assumed you'd gone out.

我没有看见你的汽车，所以我以为你出去了。

It seems reasonable to assume that the book was written around 70 AD.

认为这本书写于公元 70 年左右好像是有道理的。

I think we can safely assume (=it is almost certain) that interest rates will go up again soon.

我想我们几乎可以肯定，利率很快会再次上调。

Let us assume for a moment that we could indeed fire her. Should we?

我们暂时假设真的能开除她，我们是不是该那样做呢？

When it got to midnight and Paul was still not back, I began to assume the worst (=think that the worst possible thing had happened) .

到午夜时保罗还没回来，我开始往最坏的地方想了。

assume control / responsibility etc, [formal] to start to have control, responsibility etc or to start in a particular position or job

开始掌管/承担责任等:

Whoever they appoint will assume responsibility for all financial matters.

不管他们任命的是谁，他都要为一切经济事务承担责任。

He assumed power in a bloody coup in 1990.

他在 1990 年一场血腥的政变中上台。

Jim Paton will assume the role of managing director.

吉姆·帕顿将出任总经理一职。

assume a manner / air / expression etc, [formal] to behave in a way that does not show how you really feel, especially in order to seem more confident, happy etc than you are

表现出（装出）…的态度/样子/表情等;

Andy assumed an air of indifference whenever her name was mentioned.

每次提到她的名字，安迪都表现出无所谓的样子。

to start to have a particular quality or appearance

呈现出，显示出;

These relationships assume great importance in times of crisis.

在危急时刻，这些关系显得很重要。

The problem is beginning to assume massive proportions .

问题开始显出其严重性。

to be based on the idea that something else is correct

以…为前提，预先假定;

The theory assumes that both labour and capital are mobile.

这个理论的前提是劳动力和资金都是流动的。

Coen's economic forecast assumes a 3.5% growth rate.

科恩的经济预测是以 3.5% 的增长率为前提的。