皮皮学，免费搜题
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搜题
【单选题】
关于胎儿附属物,以下各项正确的是A.
胎盘有防御感染的功能，乙肝病毒不能通过胎盘
B.
胎盘有合成雌激素，孕激素的功能
C.
妊娠期羊水保持稳定，约500ml左右
D.
脐带中有2条脐静脉和一条脐动脉
E.
之间的气体交换，主要通过胎膜
拍照语音搜题，微信中搜索"皮皮学"使用
参考答案：
参考解析：
知识点：
皮皮学刷刷变学霸
举一反三
【简答题】分封制 名词解释
【多选题】A plane figure moves in its plane. The velocity vectors of two different points on the plane figure are the same at a instant. Which statements are correct?
A.
All points in the plane figure have the same velocity at this instant.
B.
All points in the plane figure have the same acceleration at this instant.
C.
The angular acceleration of the plane figure must be zero, but the angular velocity may not be zero at this instant.
D.
The angular velocity of the plane figure must be zero, but the angular acceleration may not be zero at this instant.
【单选题】The plane in the following figure is ( ) (Single option:10 points)
A.
Frontal plane
B.
V-perpendicular plane
C.
W-perpendicular plane
D.
H-perpendicular plane
E.
Horizontal plane
F.
Profile plane
G.
Oblique plane
【单选题】What kind of projection plane parallel line is shown in the following figure?
A.
frontal line
B.
profile line
C.
general position line
D.
horizontal line
【单选题】The plane in the following figure is ( ) (Single option 10 points)
A.
Frontal plane
B.
V-perpendicular plane
C.
W-perpendicular plane
D.
H-perpendicular plane
E.
Profile plane
F.
Horizontal plane
G.
Oblique plane
【简答题】封事(名词解释)
【简答题】封寄(名词解释)
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