引起心前区疼痛最常见的病因是()。
A.心脏神经官能症
B.肺栓塞
C.心绞痛、心肌梗死
D.急性心包炎
E.病态窦房结综合征
参考答案:C
解析:[知识点] 循环系统疾病常见症状
—How can I use the equipment?
—Well, just refer to the ________.
A.directions
B.explanations
C.expressions
D.introductions
比重瓶法测定混凝土外加剂密度,比重瓶的容积为()。
A.20ml
B.25ml
C.60ml
D.100ml