2·It is true that there are questions about the harm that may be done by the "fracking" process that liberates shale gas; there is an urgent need for systematic before-and-after environmental audits.
但释放天然气的“水力压裂”过程对环境可能产生危害的问题也是不争的事实,因此亟须对开采前后的环境进行评估。