Don't leave the engine to warm up in winter; you're burning petrol unnecessarily.

冬天的时候，不要让引擎空转，这是在不必要地费油。

youdao

In the first place you must rev it up to warm the engine.

首先你必须让发动机转起来预热。

youdao

He turned on the fan after he'd started up the engine, to give it some heat-but then it was a mammal, he figured, with fur, and it could warm itself.

汽车发动着后，他打开暖风，给箱子里的动物增加点热量——不过，他想这是哺乳动物，有皮毛，而且它自己能够取暖。

youdao

The boy hopped in the snowed-in family car to warm up, but the engine was running and the exhaust pipe was blocked by snow, causing carbon monoxide to accumulate in the car.

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