One shows the remains of a dying star four thousand light years away which has thrown off a cloud of glowing hydrogen gas.

VOA: special.2009.09.30

because someone turned the gas off and turned it back on and then left.

因为有人把瓦斯关了以后，又打开，忘记关上就离开了。

Make sure 课堂 - SpeakingMax英语口语达人

Make sure the gas is turned off.

一定要把煤气关了。

Make sure 课堂 - SpeakingMax英语口语达人

A secondary benefit is getting gas-guzzling old clunkers off the road and replaced with more fuel-efficient band new models.

VOA: standard.2009.05.18

"When the gas comes off the digester, it has not only methane in it it also has carbon dioxide And it has a trace of hydrogen sulfide."

VOA: standard.2010.02.23

"Someone could attack the industrial control systems that control all the valves, all the distribution systems, and are used to turn on and off various aspects involved with energy and the electrical power grid and oil and gas distribution networks,".

VOA: standard.2009.08.11