学进去

The world’s first fully hydrogen-powered (氢动力的) train line has begun running in Germany. The trains make almost no noise and run without ________. Germany is planning to ________ many of its diesel (柴油) trains with hydrogen trains. Recently, five hydrogen-powered trains were put ________ use in Germany.

Hydrogen is the simplest known element. It’s so ________ that it can be got without much effort. Hydrogen can be used to create electricity by ________ it with oxygen in a “fuel cell (燃料电池)”. Electricity of the new kind of train will never ________ as long as it has hydrogen. The oxygen ________ from the air around the train. The ________ part is that, when a fuel cell creates electricity, it doesn’t create pollution. The only thing it gives off is ________, which comes out as steam (水蒸气).

The hydrogen-powered trains are ________ by electricity created by hydrogen fuel cells. Because the motor (发动机) is electric, the trains run almost ________. It’s good for people both inside and outside the trains because a quiet environment is ________.

There’s a hydrogen ________ on the line to refuel (补充燃料) the trains. But since the trains can go about 1,000 kilometers ________ they need more fuel, they only need to fill up once a day. The trains can run at 140 kilometers per hour. It’s about the same ________ as that of diesel trains.