心绞痛的特点为阵发性的前胸()性疼痛感觉。
A. 刺痛
B. 压榨
C. 发闷
The actual incidence of a tax imposed on producers of a good will be borne by:
A. producers more than consumers if demand for the good is less price elastic than supply
B. consumers more than producers if the supply of the good is more price elastic than demand
C. consumers and producers equally because the actual incidence of a tax is unaffected by price elasticity
气缸漏气率分析是在活塞处于()时，采用对燃烧室加入压缩空气的方式来检查气缸相对漏气率的方法。
A. 进气行程下止点
B. 压缩行程上止点
C. 作功行程下止点
D. 排气行程上止点
耳部以听眉线为基线横断扫描时于水平半规管层面不能显示的结构是
A. 后半规管
B. 内耳道
C. 外耳道
D. 鼓窦
E. 鼓窦入口
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