Redouble your efforts and not slacken off.

要再接再励， 不能松劲。

《新英汉大辞典》

We've been really busy, but things are starting to slacken off now.

近来我们的确很忙，不过现在情况开始有所缓解了。

《牛津词典》

Nothing could make us slacken off.

什么也不能让我们松劲。

youdao

After undergoing rapid expansion about 10 years ago, it has since seen sales slacken off.

BBC: Republic chain faces administration

"The Fed's view has been that growth will slacken off on its own, " says Crosby Securities' regional strategist Manu Bhaskaran.

CNN: A PUNTER'S SURVIVAL GUIDE

Founded in 1986, as a men's denim retailer in Leeds under the name Best Jeans, Republic underwent a rapid expansion 10 years ago, but has since seen sales slacken off.

BBC: Republic chain enters administration