The following information was correct at time of going to press.

以下信息在付印时是准确无误的。

《柯林斯英汉双解大词典》

The researchers looked at time spent in a number of activities that could plausibly be driving the well-being decline.

研究人员观察了人们在一些活动上花费的时间，这些活动似乎是导致幸福感下降的原因。

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The researchers looked at time spent in a number of activities that could plausibly be driving the wellbeing decline.

研究人员观察了一些可能导致幸福感下降的活动所花费的时间。

youdao

If you took the derivative of this, you will get the velocity at time t, it would be: v=v0+at.

如果你对它求导,你就可以知道 t 时刻的速度,即,v=v0+at

耶鲁公开课 - 基础物理课程节选

Consequently, for this object the position y, at any time t is known to be 15+10t-5t^.

因此,对这个物体来说,在任意时刻的位移y,就应该为15+10t-5t^

耶鲁公开课 - 基础物理课程节选

Then, to find the meaning of b, we take one derivative of this, dx/dt, that's velocity as a function of time, and if you took the derivative of this guy, you will find as at+b. That's the velocity of the object.

接下来,为了弄清b的含义,我们取它的一阶导数,dx/dt,得到速度作为时间的函数,如果你对它求导的话,你会得到at+b,这就是物体的速度

耶鲁公开课 - 基础物理课程节选