单项选择题
Every office has a dress code,but in today’s（）workplace，they aren’t always written.
A.causal B.capable C.capital D.casual
单项选择题 Structural traps are traps（）are formed because of a deformation in the rock layer （）contains the hydrocarbons.
单项选择题 he oil（）in a source bed, and a marine shale.
单项选择题 Eventually chemical changes（）the generation of petroleum.
