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【单选题】
正常心脏跳动的起搏点是A.
窦房结
B.
房室结
C.
D.
Purkinje纤维网
E.
房室束
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皮皮学刷刷变学霸
举一反三
【单选题】If we ______ yesterday, we ______ the work.
A.
weren't interrupted... would finish
B.
didn't interrupt... would have finished
C.
hadn't interrupted... had finished
D.
hadn't been interrupted... would have finished
【单选题】—I'm not sure _____ there are living things on other planets or not. —Even scientists aren't sure about it. [ ]
A.
whether
B.
where
C.
why
【单选题】两个匀质圆盘A和B的密度分别为ρ A 和ρ B ,若ρ A >ρ B ,但两圆盘的质量与厚度相同,如两盘对通过盘心垂直于盘面轴的转动惯量各为J A 和J B ,则
A.
J A >J B
B.
J A B
C.
J A =J B
D.
J A 、J B 哪个大，不能确定
【简答题】根据以下材料，回答13-16题 某玩具企业生产经营高、中、低三种价格档次的玩具，高档、中档玩具的价格分别为100元、60元。现在开发一种低档玩具，对低档玩具进行定价；经测算，低档玩具的总投资为150万元，固定成本为35万元，单位可变成本为15元。预计销售量5万个。产品上市后，该企业拟通过尽可能多的批发商、零售商推销其产品，先将产品供应给批发商，再由批发商将产品供应给零售商并销售给最终顾客。 该企业...
【简答题】We weren’t sure about which ____ we should take.
【单选题】If we ______ day before yesterday, we would have done the job.
A.
hadn't been interrupted
B.
weren't being interrupted
C.
wouldn't be interrupted
D.
weren't interrupted
【简答题】按涂料中是否含有颜料可分为 、 和 腻子三种类型。
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