血便()。
A.粘连性肠梗阻
B.肠套叠
C.两者都有关
D.两者都无关
参考答案:B
He told me that he wanted to buy his daughter a new bag as her old onehas been stolen.
A B C D
当介质工作压力不高于1.96MPA,工作温度不高于300℃,此时阀门可用()。
A、碳素钢制成
B、铸铁制成
C、合金钢制成