中国大学MOOC: 形成水合物的条件Conditions for hydrate formation：（）

Feed is to nourish as______. () A: travel is to skate B: water is to hydrate C: throw is to fetch D: trap is to bury E: giggle is to laugh

The role and position of unconventional oil and gas resources in global oil and gas production are becoming more and more important. Which of the following are unconventional oil and gas resources? A: Tight rock oil and gas B: Mud shale oil and gas C: Coalbed methane D: Oil shale E: Oil sands F: Natural gas hydrate