符合溃疡性结肠炎病理改变的是()
A.肉芽肿形成
B.病变多局限于黏膜和黏膜下层
C.形成大量腺瘤性息肉
D.黏膜呈铺路石样改变
E.裂隙状溃疡
参考答案:B
板岩是由页岩变质而成的,固结成岩作用属于地质作用中内力作用的表现形式之一。
--- Where is Jack?
--- He _________ football on the playground with those AFS students, but I am not sure.
A.must be playing
B.must have played
C.may be playing
D.may have played