Through researching the rule of producing PWM waveforms according to Harmonic-suppressing theory, this paper puts forth the existing problem and direction of improving SHE technique.

研究了按谐波抑制原理形成PWM波的原理和规律，指出了存在的问题和解决的方向。

youdao

Thinking of past and future brings us to another problem that has foxed scientists and philosophers: why time should have a direction at all.

过去和未来带给我们的另一个问题已经被科学家和哲学家解决了：为什么时间总是朝着一个方向流逝。

youdao

The problem comes when you start to lose perspective on your work and direction.

当你开始对工作和方向失去视角时，问题就来了。

youdao

The waves were huge, and each created a problem in guiding the direction of the boat.

VOA: special.2010.03.06

Depending on the nature and the direction of the problem, a solution might be suggested in the narrative.

NEWYORKER: Town of Cats

In both cases, the problem was not just their inflammatory statements and reluctance to take direction but their diminishing returns, ratings-wise.

FORBES: Right Wing Media Gets Right-Sized

The problem is that nominal incomes and prices are sticky in a downward direction.

FORBES: Greek Crisis: Austerity Doesn't Work