It's a constant struggle to try to keep them up to par.

要使他们达到标准是一场持久战。

《柯林斯英汉双解大词典》

Remember, in physics, the potential is defined up to adding or subtracting a constant.

注意，在物理学里面，势可以加上或者减去一个常数。

youdao

Run up at a constant pace for up to 45 seconds, then jog back down and repeat four more times.

跑上山时的步子要保持不变，大约在45秒钟以上，然后再慢跑下山，这样重复跑四次以上。

youdao

so I'm heating up the system in this path here, and then to connect the 2 endpoints here, a constant temperature path.

需要再用，一个等温过程，这两个状态。

麻省理工公开课 - 热力学与动力学课程节选

This piston is being brought out, so we expect 0 the work to be negative, negative. And we start o V2 ut with zero volume. We end up with a volume p2 of V2, and the external pressure is constant to p2.

所以我们可以想象功是负的,开始的时候体积是,最终的容积是,外界的压力恒为。

麻省理工公开课 - 热力学与动力学课程节选

The accepted wisdom is for governments to be open and honest, without denial or premature reassurance, to own up to risks and uncertainties, and to keep up a constant flow of consistent information while giving people clear instructions and something to do.

BBC: Japan nuclear threat: The tsunami is the bigger tragedy

You wouldn't notice it but for a constant stream of steam billowing up to the sky from a rusty derrick.

CNN: Can Iceland's geo-thermal power re-heat its economy?

Mr Sharon, visiting China and Mongolia, kept up a constant stream of telephone calls and faxes to Jerusalem expounding on the dangers of the 13% pullback from the West Bank proposed by the Americans.

ECONOMIST: Israel