But if natural gas is not produced cleanly, it will not prove to be so cheap, either.

但如果天然气的生产过程是不清洁的，那么它的成本低廉就无从谈起。

youdao

Coal from this region is low in sulphur, and so burns more cleanly, but has a relatively low energy density unless treated.

该区域的煤含硫量低，也因此更为清洁，但是在处理前能值(energy density)相对较低。

youdao

The good news is that expat compiles cleanly on most Unix systems, so installation shouldn't be too difficult.

一个好的消息是，在大部分Unix系统上expat可以干净利落地编译，所以安装不应该太困难。

youdao

So the first hope for the new season is that whoever wins the league does so cleanly.

BBC: Welsh Premier preview

Like the late Ralph Shapey, Mincek has a knack for etching jagged figures so cleanly that they take on a sculptural quality.

NEWYORKER: The Long Haul

We would bridge the short-term problems with reasonable and safe development of fossil fuels, while simultaneously setting an agenda to not just produce energy domestically, but also to do so cleanly.

FORBES: Is America Too Near-Sighted When It Comes To Gas Prices?