It has a lot of disadvantages: each one of these steps is extremely expensive, it's potentially dangerous and they have the interesting property that the step cannot be performed in anyone's backyard, which is a problem.
但它同时也有很多不足， 这里的每一个步骤都很昂贵， 也有安全隐患。 而且有趣的是， 任何步骤都不可能在家门口完成， 这是个麻烦。