胃黏膜癌主要在胃壁的哪一层内扩散
A．肌层
B．黏膜下层
C．黏膜层
D．浆膜层
E．以上均不正确
参考答案：B
That hero who died in the war was so brave that he never ______ to the enemies until death. [ ]
A. gave in
B. gave out
C. gave up
D. gave away
当锅炉汽压低于蒸汽母管压力（）时，缓慢开启主汽阀，进行锅炉并汽操作。
A.0.02~0.05MPa
B.0.05~0.06MPa
C.0.1~0.2MPa
D.0.08~0.09MPa
