覆盖在储油气层之上、渗透性差、油气不易穿过的岩层，它起着遮挡作用以防油气外溢的作用的岩层称之为什么？
参考答案：盖层
— Have you seen the film Under the Hawthorn Tree?
— Of course, I have . It was in my village ________ it was made. [ ]
A. that
B. where
C. when
D. which
蒋介石第六次围剿的主力军是（）。
A.东北军
B.东北军和晋绥军
C.无产阶级
D.晋绥军
