It rained without letup.
雨下个不停。

When will this rain letup ?
雨甚麽时候才会停呀?

There was never a letup in the noise.
喧闹声一刻也没有停顿下来。

There is no sign of a letup in the hijack crisis.
绑架危机毫无缓和迹象。

We must develop the advanced productive forces without letup.
我们必须坚持不懈地发展先进的生产力。

Thus, little by little, the product can shows its charms that will never fade without a letup.
产品才能在细水长流中展现历久弥新的经典魅力。

Now the fight to ferret out the Rightists must go on without any letup, and we must keep up the strong gale and torrential downpour.
现在, 右派还要挖, 不能松劲, 还是急风暴雨。

That night it grew very windy, and the next day a light rain fell, followed by a heavy downpour which continued without letup into the afternoon.
当夜刮大风，明天小雨接大雨，一脉相延，到下午没停过。