Special production processes are needed to make pipes for carrying hydrogen. For that reason, few exist.
特别的生产过程就需要制造管道运输氢气，由于这个原因，氢能也很少见。
2
Special production processes are needed to make pipes for carrying hydrogen.
为了使管道能达到运输氢气的要求，专门的生产流程是必须的。
3
Of course, looking for hydrogen sulfide-eating microbes that ooze elemental sulfur means that we'll be looking for similar biological processes we observe on Earth.