It is usually economical to buy washingpowder in large quantities.
大量购买洗衣粉通常要省钱些。
《牛津词典》
2
It nearly always makes sense to produce bulky chemicals, such as washingpowder, where they are sold, to keep transport costs low.
对节省物流费用来说，在当地生产运输笨重的化工产品，例如洗衣粉，有着明显的好处。
3
They may be merely additions to existing product lines (the first cigarette with a filter tip, for instance) or improvements to existing products (a new whiter-than-white washingpowder).