Turn on the gas.

打开煤气。

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if you turn on the lights when there is a gas leak,the house may explode. ;

如果在煤气泄漏的时候 开灯,房子就可能会爆 炸.

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If the gas is turned off, a professional will be needed to turn it back on.

如果天然气关掉了，就需要找专门人员来把它重新打开。

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"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

In the wintertime, he used to turn on the gas stove and close all the doors, so it got real hot in there.

NEWYORKER: We Are Alive

Pre-cook it for at least two hours. (Fill a stockpot with water, add lemon juice, some salt and turn on the gas.) A savory, warming bowlful proves the sumptuous ends justify the malodorous means.

WSJ: Cooking With Tripe: No Need to Gripe | Jolie Laide

To supply the extra juice, utilities turn on inefficient single-cycle gas turbines, which turn 25% of the fuel's energy into electricity, as opposed to 45% for combined-cycle plants that use turbine exhaust to make steam to run a second generator.

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