硝酸(HNO3)中氮(N)元素的化合价为()。
A.-2
B.+2
C.+5
参考答案:C
I try to make him understand that I’m not interested in him, but he never gets the ____.
A.information
B.news
C.message
D.word
下列关于呕血的描述,不正确的是()
A.病因最多见于消化性溃疡
B.出血方式为呕出
C.血中混有食物残渣、胃液
D.酸碱反应为碱性
E.出血前有上腹部不适、恶心、呕吐