翼点叙述错误的是
A. 位于额骨、顶骨、颞骨和蝶骨四骨的会合处
B. 该处骨质薄弱
C. 蝶骨、顶骨、筛骨和上颌骨四骨的会合处
D. 构成“H”形的缝
E. 内侧有脑膜中动脉通过
地铁的特点有哪些?
A. 运营能力强
B. 施工简便快捷成本低
C. 施工成本较高
D. 施工专业复杂 ,涉及主体多
Infixeddisplacementvanepump,
A. flowrateisconstantanddoesnotchangewithworkingpressure.
B. flowratedecreaseswithworkingpressurerising.
C. flowrateincreaseswithworkingpressurerising.
D. noneoftheabove
Whatistheadvantageofvanepumps?
A. smoothrunning
B. lowpulsationofoutput
C. quietoperation
D. alloftheabove