以下与呼吸困难无明显关系的疾病为（）
A.肺炎
B.急性胃炎
C.大量腹腔积液
D.急性一氧化碳中毒
E.脑出血
参考答案：B
水螅体壁由两层细胞组成，外层是______，内层是______．两层细胞之间有一层没有细胞结构的______．体壁围成的空腔叫做______，它与______相通．口的周围有______，它能______．
My mother would stay at home to watch TV ______ out for a walk. [ ]
A. than go
B. than going
C. rather than going
D. rather than go
