Cleaning dust manually is not practical because of the scale of the installations and the scarcity of water in desert regions.

由于太阳能装置的尺寸很大，而且沙漠地区干燥缺水，因此人工清除尘土是不切实际的。

youdao

Some rate higher on one person's scale than on another's. Some are practical, some are quite silly.

有的有关联，有的没有，有的进度在这个人身上比那个人身上更有成效，有的实用，有的愚蠢。

youdao

In fact, you can scale a site many ways, and multiplying servers is but one (albeit often practical and necessary) approach.

实际上，您可以通过许多方法扩展站点，而增加服务器只是一种(尽管通常是实用并且必要的)方法。

youdao

Any device would also need to be packaged in a way that made it practical - on the scale of an ultrasound scanner, for example.

BBC: Laser 'lights up' cancer

Building on the craze for corporate jets--more than 550 are expected to be sold worldwide this year--manufacturers are busily exploring how to create a practical and affordable small-scale model that can let executives fly privately in excess of the sound barrier.

CNN: ASIANOW - TIME Asia | Travel Watch

As the world's largest democracy, India knows a great deal about large scale elections - and their practical difficulties.

BBC: World 'smug' at US fiasco