GRE Text Completion: JiJing 1373-GRE填空机经1373题 - V8V1BTORZLK87T79A

Conventional deposits of oil and gas are actually the final resting place of far-traveled hydrocarbons that were (i)____________ deeper source beds of organic-rich rock. By contrast, shale gas (ii)____________ its birthplace, remaining in the source bed whose organic matter produced the gas. A. trapped in B. never leaves C. generated in D. swiftly escapes from E. bound for F. rarely stays in