More recently Britain's BP bought several American oil companies, triggering a wave of oil mergers in America and Europe. 最近英国石油公司购并了几家美国石油企业,吹响了美欧石油业界合并的号角。
An environmental tax is therefore necessary to induce the oil companies to internalize the environmental costs that their activities impose. 因此环境税是引导石油企业将他们造成的环境成本内化的必要手段。